Their stocks may act like roller coasters, but it's been a long time since investors last enjoyed investing in homebuilding stocks. Yet the latest news out of the National Association of Home Builders, in cooperation with Wells Fargo (NYSE: WFC), just might put the "fun" back in housing market fundamentals.

Reporting its most recent Housing Market Index (HMI) results yesterday, NAHB/WFC told a tale of renewed -- or at least renewing -- confidence among market participants. I could describe what happened for you, but perhaps it's best if you just see for yourself:

See those triple spikes over on the right side of the chart? Those indicate sharp upturns in homebuilder confidence. Prospective buyer traffic is up off recent lows. Expectations for future sales are up, too. And wonder of wonders, even actual, honest-to-goodness sales of homes seem to be improving!

Of course, when all is said and done, the composite HMI still reads a score of just 16. That's better than last month, but considering you need a score of better than 50 to prove a definitive bull market in housing, I can understand why there have been no reports of over-joyous house parties at Toll Bros. (NYSE: TOL) and Pulte (NYSE: PHM) just yet.

To hear the homebuilders tell it, that's mainly the bankers' fault. They'll tell you that what's really keeping a lid on the party is the difficulty of getting major lenders like Bank of America (NYSE: BAC) and JPMorgan Chase (NYSE: JPM) to cough up a construction loan. Say the builders: "You can't sell what you can't build." They're having trouble obtaining financing "for new-home construction [despite] inventories of completed new homes [being] quite thin."

Foolish forecast
Now, maybe you think that the bullish sales reports out of Lowe's (NYSE: LOW), Home Depot (NYSE: HD), and Wal-Mart (NYSE: WMT) this week would bolster bankers' confidence in housing demand; get 'em to loosen the purse strings and give this rally a boost. Banker in Chief Ben Bernanke's $600 billion bet on "quantitative easing" should, in theory, give them the dry powder they need to explode this market upward.

Yet the bankers are making good money just reinvesting in Treasuries, milking the GM IPO for profit, and generally sitting on their hands ... and their cash. In this environment, what are the chances they'll actually go out on a limb and take the risk of, you know, doing actual banking business?

Investors can hope for the best, sure. But me, I'm preparing for the worst.

Take the Foolish Rorschach test. Do you see something different in today's chart? Tell us about it below.

Fool contributor Rich Smith does not own shares of any company named above. Rich is not a licensed economist, but he plays one on the Web. Check out his latest stock recommendations on Motley Fool CAPS. The Motley Fool has a disclosure policy.

Home Depot, Lowe's, and Wal-Mart are Motley Fool Inside Value choices. Wal-Mart is a Motley Fool Global Gains selection. The Fool owns shares of Bank of America, JPMorgan Chase, Lowe's, and Wal-Mart.

Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.