Darker colors disguise fat rolls better, I've found. And not-tucked-in waists.

I have this one cycling top I love, the Sugoi Bella Tank

http://www.teamestrogen.com/products.asp?pID=17606

which I first got in black, but then I thought I had to have the red, too. It is very tight fitting, but scrunches a little in the front. So when I finally got the red- OMG, the rolls!! But then I figured, so what, I'll just suck in when I'm around a camera, and make sure it is tastefully scrunched at other times- but only because I love the top.

Would you maybe be less self-conscious in a regular swim suit for the swim, then pull on tri or bike shorts for the bike/run? I've done that before- it's not ideal, but it works.