Cheap-arse competition, the prizes are better on OC3D !
For my company's 40th birthday competition, 40th being pretty huge, I'd have something like a vip visiting trip, to which u'd be able to pick components for a full pc build. Top 3 prizes maybe. (plus parent if applicable)
2nd band of prizes the best cpu + a mobo + card
3rd band perhaps some cards
Total cost wouldn't be 10s of 1000s.
Topped off with a massive advertizing drive that would cost more, but have some benefits.
A 'cost' 4890 card won't cost them anything.
The prizes as they stand would hit their books for a few thousand maybe.