The only serious experience I have brokering JVs for physical products are 'hard' versions of infoproducts. Basically, it is the same ... sometimes it's even easier to sell, as customers feel having the ability to see and hold the physical goods in their hands a quality edge over digital, in my experience ... you may have to eat into your own profit to secure 50% commissions for your partners, as they've been spoiled with 75% to 100% commissions on digital merchants looking to built customer lists with little regard in making actual profit from the launch, monetarily.
The problem is fulfillment costs for each and every unit, unlike digital. So you have to work extra hard on retention/CS, and save full version physical comps for proven partners. If not an infoproduct, I'm sure sample versions would be the best route to secure and oblige partners, and I've no doubt that the usual partner profit margin would have to be cut considerably. Shouldn't be as much of a problem as it would appear, considering that other niches are not quite as jaded as IM in regards to high commissions.