Prolly wrote a nice review of baspin/freestyle forks on his blog. http://prollyisnotprobably.com/2009/01/forks.php
The first bad new is that the supersexy BMW Gangsta forks is officially NOT designed for tricks, so if you want to go hard on this bike you need a different and beefy fork.
Second bad new is that every single dirt jump fork like the Black Market, Charge or DMR and even the new Volume is too long and if you put them on your track frame the geometry is going to be too slack/relaxed.
Third bad new is that the only good forks seems to be the new MKE and Charge but they're not avaiable, we have to wait.
For me the result is: if you want to barspin on a track frame with trackish geo the only option is to put a 650c front wheel.