Some product launches have huge cash prizes for pre-launch leads and then bigger cash prizes for sales during the launch.
I've seen some truly ridiculous prizes: a VW Beetle from the 70's, zero-G flights, sky-diving, a ride in a fighter jet, etc.
Then of course there's your more typical prizes like vacations, cruises, motorcycles, cars, laptops, smartphones, etc.
For both your pre-launch and your launch contests, you'd give out prizes to anybody who makes X number of sales or refers X number of leads. This way, it won't only be the top 10 JVs (for example) who win something. It would discourage some JVs if they knew they had no chance of winning a prize.