The Greatest Movie...

... that would fit the definition:

"A light-hearted version of They Shoot Horses, Don't They?"?

Hands on a Hard Body (1997)

I'm telling you, those two pictured there
are the romance of our times.

First off, anything is light-hearted next to They Shoot Horses, Don't They? which is an exercise in grimness. Hands on a Hard Body is basically an updated, documentary version of the same story - where Horses was about Depression-era dance marathon competitions where people would dance for weeks straight for some cash, Hands is about those car dealership contests where people stand with their hands pressed to the body of a truck for days on end in order to win said truck - and it's hardly without its fair share of social commentary, but it's not nearly as scathing as Horses.

Which suits it nicely. The characters lined up for this twisted display of commercial masochism speak for themselves, and the filmmakers let them. The film appears to be super low-budget, using low quality video (it looked like the videos my uncle would take at family birthday parties in the 90s) with the sort of graphics utilized in small city news broadcasts from the same era, which lend it an air of impartiality. But a voice peeks through here and there - say, a purposefully slowed-down shot of a hand slipping off the truck at an incredibly timely moment.

Here's the film's trailer; it's definitely worth seeking out if you can find a copy (it's not readily available on DVD):

. . .

ETA I went looking for word of Robert Altman's planned remake of this flick (see the comments), a prospect that ended with Altman's death obviously, and I found a pair of posts where the film is discussed pretty thoroughly in light of a tragedy that occurred in 2005 during one of the contests. Check it here, and then here for more. But only if you've seen the film already. Sadness.
.