The coming months could prove to be an enticing time for investors. Many stocks are trading well off their highs under the assumption that the coming streams of economic data will prove to be disheartening. If we indeed are in for a tough slog in the months and quarters ahead, then many of these stocks could meander at their current cheap valuations. But even modestly good news on the economic front could sharply boost interest in stocks, as we may be looking at the beginning of a sustained economic upturn.

We can use 2002 as a reference point. Prospects were glum and many stocks sported low P/E ratios. That set the stage for a powerful two-year run that pushed the S&P 500 up +23% in 2003 and +11% in 2004, while a range of individual stocks doubled off of their lows. With that in mind, here are some stocks that could sharply benefit from a more positive economic backdrop or simply better news out of quarterly results.

Winnebago (NYSE: WGO)
In early June, shares of Winnebago soared after the company announced that sales in the all-important spring season were very robust. Management noted that demand for recreational vehicles was quite strong compared to a year ago, though below levels seen just a few years ago. The euphoria eventually faded, and shares have lost nearly -40% during the past three months.

Winnebago’s rebound may prove to be erratic. After all, the winter months can be fairly lean. But if investors start to see signs that the consumer is beginning to spend, then Winnebago will be seen as a prime beneficiary of an improving economy. It’s important to remember that consumers that were relatively financially healthy heading into the downturn have also sharply boosted their savings rate. At some point, those consumers may feel comfortable treating themselves to high-ticket purchases.

After the recent sell-off, shares now trade for about 20 times fiscal (August) 2011 forecasts, and more importantly, six times annual profits in the middle of the last decade when the industry was at its peak. Demand for RVs should eventually rise back to that peak, as the amount of baby boomers continues to grow. Assigning a multiple of 15 off of those peak earnings would push shares up to $30, nearly +200% above current levels. That price target is unlikely to be seen for several years, but for patient investors, Winnebago could be a real home run.

A123 Systems (Nasdaq: AONE)
This maker of advanced battery systems was initially a hot IPO, but perhaps came out just a bit too early. The company posted several lackluster quarters after going public, sending shares down from $28 to under $8. Shares have started to rebound in recent sessions back up $10 as investors start to realize they were judging the company’s results while the electric car market has yet to really take off. But it will. Soon after the Nissan leaf is released in late 2010, a slew of additional electric cars will hit the market from companies like Mitsubishi, Smart, Chrysler/Fiat and perhaps BMW.

As investors start to re-focus on this potentially massive market, shares are likely to turn over a new leaf, perhaps back up above the $20 mark. The next few quarters will likely be lackluster for A123 Systems, so these shares will only benefit in a rallying market as investors once again focus on high-growth opportunities.

Biodel (Nasdaq: BIOD)
This medical device company holds a great deal of promise — or at least it did until investors lost interest, pushing shares down from nearly $20 in the summer of 2008 to a recent $4. But a rebound may be in the offing.

Biodel has developed a device that injects insulin into the bloodstream more rapidly than other approach. The device can automatically respond to blood glucose levels, regulating the amount of insulin required. After several years of anticipation, Biodel is moving closer to the regulatory finish line.

The insulin device has had a very strong safety profile and has been quite effective in clinical trials. FDA approval could come late this year, and the company may sign key partnerships before then. Might shares once again re-visit those lofty levels seen back in 2008? Time will tell.

Deer Consumer Products (Nasdaq: DEER)
I’ve written about this company several times before, usually when management boosts guidance and extends a current share buyback. That’s about all they can do to support the stock, which continues to find little love in this market, despite stellar growth prospects.

Deer makes kitchen appliances for global brands like Stanley Black & Decker (NYSE: TK), and is now ramping up domestic sales, steadily building its brand among Chinese consumers.

The Chinese economy will likely cool off from its recent torrid pace, but the Chinese middle class looks set to keep expanding. Sales grew +86% in 2009 and look set to grow another +97% this year and +28% in 2011. Meanwhile, shares trade for little more than half their 52-week high, as China-based stocks of all stripes get heavily discounted in this market. Assuming shares trade up to 18 times 2011 profits, investors are looking at a two-bagger.

Denny’s (Nasdaq: DENN)
Management at this restaurant chain has tried every trick in the book to boost sales, from special breakfast deals to two-for-one specials. But sales are still in a slump, after falling sharply over the last two years. Management may simply need to wait until consumers are spending again, at which time sales could rebound at a decent pace and profits at a more robust pace. This is a very high fixed-cost business, which historically has been marked by profits that grow twice as fast as sales.

Investors don’t need to see Denny’s rebound all the way back to full health — they simply need to start seeing more positive trends and then extrapolate future results from there.

Even with the sales slump, Denny’s remains profitable and trades for about six times next year’s projected EPS of $0.43. Looking out several years, EPS could rebound to the $0.60 or $0.70 level. Slap a multiple of 10 on that and shares could rise to at least $6 — double or triple current levels.

Action to Take –> Winnebago, Denny’s and Deer Consumer Products are unlikely to fall much further, even if the economy remains in a funk, thanks to supportive fundamentals. They each represent roughly +100% to +150% upside. Biodel and A123 Systems are more speculative and do have some downside risk, but also represent even sharper upside potential. A basket of these stocks stashed away for a while may prove to be a winning move.