Heated renegotiations are under way on a number of rich production deals as studios re-evaluate the return on investment for deals that carry enormous overhead -- in exchange for (hopefully) hit movies.

At the heart of studios' scrutiny of production deals are these issues: the number of employees they're willing to pay for, and how generous a gross-point deal they are willing to accept.

"It's become a very tight-fisted environment," said one producer. "Everything's being scrutinized in the name of cost-cutting."

The climate is particularly heated at Sony, which has more deals than any other studio (a total of 35, including those at Revolution).

Several production deals will not be renewed when their contracts are up over the next several months.

One of the lot's biggest producers, Douglas Wick and Lucy Fisher's Red Wagon, produced recent long-legged hit "RV" but also gave the studio the miss "Bewitched" and a middling performer in "Memoirs of a Geisha." Wick and Fisher are in the midst of renegotiating the Red Wagon contract, which expires soon.

While the outcome isn't clear, Red Wagon has some negotiation leverage, as it is said to be courted by other studios, such as Paramount.

As for Revolution, its contract with Sony expires at the end of this year, at which point Revolution founder Joe Roth will segue to a producing deal at the studio.

Sony would not comment.

Meanwhile, Par is in the process of its own reshuffling: The future of one of its -- and the town's -- more expensive studio deals, that of Cruise/Wagner, is currently in doubt.

The shingle's contract with Par expires Aug. 31, and insiders say Par is ready to pass on a reup. But one CAA rep says negotiations are ongoing to keep Tom Cruise and Paula Wagner on Melrose.

Although the company has provided Par with some heavy hitters at the box office -- "War of the Worlds" and May's "Mission: Impossible III" -- it has also delivered a string of recent disappointments like "Suspect Zero," "Elizabethtown" and "Ask the Dust."

If a deal can't be made, Cruise/Wagner is not likely to find itself homeless. Studios are hungry for star deals, and, overall, Cruise/Wagner has had a successful track record while delivering a lot of prestige.

However, if Par keeps C/W, the deal may not come with the same points as it did before. Paramount is a different studio than it was when C/W built its home there. When Brad Grey took over as chairman in March 2005, one of his first priorities was cutting the budget on "MI3."

Also, Cruise's deals are notoriously rich and hard to make, and Grey's work with the J.J. Abrams-directed pic was a sign that the studio was ready to reel in spending even when it came to a project from its two biggest producers.

So it wouldn't be surprising if Grey does the same with their studio deal if they do end up re-extending their pact.