window motors are pretty powerful, but are notoriously badly made. Very similar to cranking motors, in that they are enormous power pigs, shoddy construction, etc since they have a very low duty cycle.
seat motors, and many of the small " only runs for a few seconds" motors found in cars & trucks are just as bad.
Did you ever watch Robot Wars?, one of the best robpots was called Cassius, and it was really the first to be self righting, and was famous for actually flipping up in the air and landing back on it's wheels - I think it won at least two wars?.
Anyway, the guy (Rex something? - Garrad?) who built it actually makes special effects, for movies and anyone who wants them (moving displays in museums etc.)
He's been using Bosch wiper motors from scrap cars (probably the most common kind?) for years and years, usually running them at 24V so they run faster, and he claims NEVER to have had one fail!.