X-prize proposal for Red Dragon payload

I think SpaceX should create an X-prize for rovers to be included in a Red Dragon mission. Gather proposals for rovers in the 100-200 kg range, like Spirit and Opportunity, but you might have more restrictive volume constraints. The 10 best proposals get $100,000 seed capital and then another $100,000 if they show they can actually build something. Before launch pick the 5+ most promising ones and send them to Mars. Best one wins $2 million, second best wins $1 million. Total cost $5 million or less. The biggest drawback would be the risks and complication of dealing with unknown rovers.

Rovers could collect samples for ISRU tests, deploy any other equipment SpaceX wants to send, and dig pits to photograph the layers of regolith and rock. They could also practice completing simple tasks autonomously like in the DARPA Robotics Challenge.