Hi Barefootsies,
I read your post. You are asking for someone to invest in new (to you) niches, and fly out to your neck of the woods a couple of times a month, to show you how its done. I can't say for sure, but I don't think you won't get too many takers here as everyone is already pretty busy doing their own thing.
I have a better idea for you if I may.
Why not place an ad on some fan based boards looking for someone who REALLY loves the niches you are looking for, and hire them as a technical advisor instead? You can qualify them by asking them to prove they truly know and love their stuff by showing you the membership bills they have from all of the sites they have joined (and why).
Not only will you get the expert of a die-hard fan of lesbian/feet niche stuff, but you will also learn exactly WHY he loves particular pictures or websites. You will learn exactly what to shoot to gain this kind of customer.
Since you already have lots of online business experience you probably don't need an expert to tell you what to do in that area. A "Technical advisor" will cost you alot less money as you can put him on payroll instead of give up any percentage of your business to him. You save money, save legal headaches, learn alot, and give someone a "dream job" for a while...
Just my 2 cents!
Good luck with your quest.