These are my newbie (year and a half experience) observations and thoughts:

Getting any affiliate or JV partner all boils down to helping the other person, not the other person helping you. "What's in it for me" is always what the 'other' person is thinking. Start there.

Now in terms of JVs outside of IM, you would think of how you an increase the other party's sales. If you can increase someone's sales, they will always be interested. If you just want to piggyback on the other party's success, they will not be interested.
If we take this over to IM, we have to think in the same terms. The bigger names always have products to launch. They are interested in branding themselves and helping you launch your product is not helping them a bit. If you're 'in the club' already then thing change and they want to help each other out, contests get their competitive juices pumping, etc. But for us newbies, we have to think in terms of how we can increase the other person's presence, branding and success.

How to do that is not so easy or apparent.

What I'm trying out right now is to invite some of the bigger players to include one of their free or up-sell product with mine. I don't know, maybe I'll even have to produce the product for them and offer to put their name on it. Talk about bribery! When people buy my product, they'll get the freebie or have an opportunity to buy the up-sell. Either way I get the bigger name on my product page either before or after the sale and that can't hurt. I don't expect any of the bigger names to mail for me because of that but they might notice me for a later promotion. At that point it will boil down to how well my product converts.

What do you think of this approach? Do you think it will work?