Hi not all the Dohc turbo engines were in FPV vehicles, and there will soon be 3 Ford vehicles available - The XR6 Turbo Falcon, The Territory Ghia Turbo and the FPV Typhoon & Tornado Ute. The XR6 and Terrirtory run a 245kw version of the Dohc Turbo engine and the FPV's run a 270kw version.
The FPV is a relitivly new addition to the line up and has only been around for about 18 months at the most, and is therefor an unlikely source for the engine. On the other hand the XR6 Turbo has been around since late 2002 and is far more available. Last time I looked on Australia a Dohc Turbo I6 and 5speed second hand from a dismantler was about $3500AD