Eight-year-old Zipp track wheels had problems with their hubs. You may want to avoid those.
As for Pro Elite's, they are extremely heavy and while they make a reasonably stiff wheel, they are heavier than they say they are and I've found the tire bed isn't shaped as well as I'd like for typical track tubulars.
How fast are you riding, or what category? Unless you're riding quite fast and winning, a non-aero rim won't necessarily kill your performance. If you're starting out, I'd suggest a classical pair of low-profile tubular rims like the Arayas simply because they are easy to true, durable, comfortable, and you'll always be riding on training wheels more than race wheels anyway.
If, like the rest of us, you just have to have some nice race wheels, I'd actually suggest new Zipp rims on some Phil Wood track hubs. Rich Sawiris, John Dacey, and others can build you a stellar pair of wheels that way and save you money over new Zipps and over most of the alternatives. Get them with the 360 track rim or, if you really want aero, the 808 road rims. I find the 360 has a bit more lateral stiffness which is more important on the track, but the 808s are virtually as aero as a full disc without the wind issue.