Construction equipment renter United Rentals is building a better future one disappointed short-seller at a time, writes MoneyShow.com senior editor Igor Greenwald.

Netflix (NFLX) and Sears Holdings (SHLD)…Bank of America (BAC) and JCPenney (JCP)…this is shaping up as a biblical year, in the “last shall be first” sense.

Every big loser from 2011 looks like a short squeeze candidate, and the cloudier their business prospects, the better, it seems. It’s enough to send one combing through the list of the most heavily shorted stocks for other laggards and no-hopers.

This is not a place one expects to find a stock that’s just broken out to a 13-year high, and a company that’s just blown through its sales and earnings estimates on the strength of a favorable secular trend and an incipient cyclical upturn.

And yet that’s just what we have in United Rentals (URI), the leading renter of backhoes, earthmovers, and other heavy equipment to a construction industry no longer eager to buy such big-ticket items outright.

None of the construction markets in the US has even properly turned up yet, but URI has been making hay for the last year from the growing popularity of its rentals.

On Thursday, the company reported a 25% year-over-year revenue surge, beating the consensus forecast by 8%. Earnings excluding one-time charges came in at 82 cents a share, 24 cents above expectations.

On the conference call following the results, CEO Michael Kneeland noted that spending on residential construction remained flat last fall, according to the latest government statistics. Yet URI’s business continued to boom, as it captured market share in a fragmented and largely privately owned industry.

“Our sales force is finding that customers are more active and optimistic than a year ago,” Kneeland told analysts. “So we think there is an early upswing that’s not fully reflected yet in the government data.”

A lasting pickup in construction would be a tremendous boon to URI, which is in the process of acquiring its largest rival. Distinguished hedge fund manager Oscar Schafer, who named URI as his top pick in a recent Barron’s roundtable, estimates the stock could top $60 in a full-fledged recovery.

Of course, the stock has already run quite hard. Counting this morning’s gain, it’s up 30% since the beginning of the month and 142% since early October, not to mention up from $3 a share in March 2009.

But as of two weeks ago, 29% of the public float was sold short, equivalent to six days’ typical trading volume. So there should be plenty more bears around to get steamrolled.

Incidentally, EBIX (EBIX), a cheap small-cap supplier of highly specialized and popular software for the insurance industry—and mentioned here last month—is another heavily shorted name that’s been moving up of late.