I'm gonna use my ex as my 'dream girl'. Always wish we had lasted longer together.
1. ...let her take a picture of you naked?
Easy of course!
2. ...get naked in a risky public place?
I'd love for her to strip me down where I might get caught.
3. ...act like a little boy and call her "momma"?
This doesn't turn me on as much, but I'd be down for it if that's what it takes
4. ...let her give you a spanking?
She can hit me as hard as she likes!
5. ...eat her out until she has an orgasm?
Is this even a question... YES!
6. ...masturbate in front of her?
She can watch me all she likes"
7. ...let her pee on you?
I'd open my mouth just for her!
8. ...strip naked in front of her friends (guys and girls)?
If I knew it would stay within the friends then maybe, not sure though.
9. ...taste your own cum?
If she feeds me it 
10. ...obey a strict diet and exercise regiment for 3 months?
Maybe not so much this one
11. ...dress up like a school girl with a mini skirt, stuffed bra, panties, wig and makeup?
If that's what she wants then yes, as long as its between us and no one else
12. ...go without sex or masturbating for 1 year?
I'd count down the days until I could cum, hopefully I can still please her
13. ...let her tie you down first?
Again this is a win for me bring it on!
14. ...shave off all of your pubes?
I do it myself anyway so it's not a problem
15. ...dress up like a french maid and do chores for her?
I'd make her house spotless
16. ...let her put clamps on your nipples?
As long as they don't hurt tooo bad
17. ...cum on your own face?
I'd be honoured to cum wherever she told me
18. ...let her fuck your ass with a strap on?
This would be a dream come true, literally
19. ...strip naked on a live webcam?
If I knew I wouldn't be recognised, why not
20. ...suck her gay friend's dick?
As long as she watches and gets off from it
21. ...let him cum in your mouth?
Might aswell go all in
22. ...let 5 or 6 of her girl friends fuck you with strap-ons and dildos while you eat them out?
Again this is borderline my fantasy
23. ...have a threesome with her and her guy friend (you give and receive)?
Yeah of course, closest I'll get to having sex with her alone!
24. ...be her sex slave for 3 months (she gets to do whatever she wants, mix between conventional sex and femdom)?
I'll be her slave untill hell freezes whatever she want's im there
25. ...be her bitch for 1 week (no sex, but a lot of dress up, chores, humiliation, and oral for her and her friends (guys and girls))?
I think its not too harsh a price to pay