I have six conversions and a Van Dessel Country Road Bob. I have yet to own/ride a true track bike.
Part of the fun with conversions is the ever ongoing quest for parts. I'll buy wheelsets off of eBay
and then begin looking for a frame to go with them. It takes less than an hour to strip down a frame
of the deraillers and stuff. If you decide on using a rear brake the dropouts don't require as much
adjustment as would track ends. A custom built track bike would certain look great, but my current
bikes all get me where I'm going well enough.

Conversions to date:

Motobacane Nomade (52x18t, started off 42x18t)
Motobacane Mirage (52x16t)
Schwinn Le Tour (42x16t)
Lotus Elan (42x16t)
Miyata OneTen (52x19t)
Free Spirit (Austrian made, 52x18t)