Aeroheads + 6600 Ultegra front hub + All-City rear track hub + double butted spokes will cost half of what either of those frames cost, and your bike will feel twice as much better. You get to keep your smoother ride, drop something like 3,000 lbs. of rotating mass, and you still get to ride a good looking wheelset that comes in all the Velocity colors (and you can even find them non-machined). Plus, I doubt it will be hard to sell a B43 wheelset. If you want to climb better, accelerate faster, and generally enjoy street riding more, lighter wheels will make a much bigger difference than either of those frames.

Oh, and if the Pista frame can be easily stripped to just chrome, do that. It will look and ride like a whole new bike, and should be doable for under $300 depending on who builds the wheels.