Must be max of 3-4 years old with low miles.
I just switched to a 700c tt bike, and have my old 650c race wheels for sale. I’ve got an Elite/Zipp 404 front (Zipp 404 rim with no dimples - but no 650c rims have them - built with Sapim CX-Ray spokes and a White Industries hub by Elite Bikes in Philly) that rolls like butter. For the rear, I have both a Zipp dimpled disk and a Hed Alps tubular. Personally, I’d never race without the disk (I’m light at around 140 lbs), and although I’ll admit I don’t understand the physics behind it, the bike is just much more stable racing with a disk than dual deep dish rims (something around the center of pressure being moved rearward). The front has 2 seasons of racing only (although three season old as I was injured in '07), the rear has 3 season of racing only (4 years old for the same reason) and the Hed has about 150-200 miles on it.
All are in excellent condition. If you’re interested, I’d put together a package for the lot of 3 wheels for $1,100.
I have a set of 310s for sale. They are brand new and have never been ridden. There is a link to pictures in my signature.