Steerer extension / replacement?

[Mackerel]

Hi all,

I've been looking for some P2 forks for a 1992 Explosif, and it seems to me that most of the "correct" forks are threaded and have steerers that are too short for my needs.

Please does anyone know a good, and cheap, frame builder or repairer who could graft an extension onto some P2s? It must be a pretty simple job that would solve a problem that's common to a lot of folks on here who need specific steerer lengths...

Any ideas?

Thanks as ever,

Jason