I agree there's lots of places where one could find potential partners, but that's where it usually stays...potential partners.
To find reliable partners who really want to do a proper JV is a lot harder lately...so I've learned the hard way.
I'm finally getting through to a few very good potential partners who saw my product and think it's a great product with huge potential. First I'm trying to keep in touch with them regularly...not begging them to promote for me, but just conversation, tips, questions, etc..
To have the best product in the world won't mean people want to do a JV with you though. For quite some time I couldn't show them any conversion rate numbers (still can't prove EPC), because I had no effective way to draw traffic to the page. But hopefully that will change soon. I've been asked if my product can be used for an upsell on a promising launch...that's already something innit...
From the 50 you approach you can probably count on 1 or 2 who are actually interested in working with you. That's what I've seen up till now. Once your name is more known in your market I believe it's easier to find better and more partners. But it's still "I scratch your back, you scratch mine...". Logically I'd say and it will always be like this when you're starting out with your first serious product.
Andre