I just saw a deal for the jaton 128mb ti4200 for $128. The cooler on it is the same green rectangular one that comes on standard geforce 2 ultra to geforce 3 ti500s. It also has the push pins in the cooler which is needed for the crystal orb.
the crystal orb will physicaly fit, but the pin things wont align up right so you`d have to use some thermal epoxy.
thermaltake tend to release a new GPU cooler for each new series of the geforce cards. blue/orange orb for gf1/2, crystal orb for gf3 and the gf4 copper cooler.
i`d buy the the gf4 copper cooler personally cos it comes with some ram sinks. but, if you already own a crystal orb, then buy some thermal epoxy, but, for the same price as the epoxy, you can get the gf4 copper cooler, your choice really.