Cream of the crop:
jerms MkI
D*A*M 1965

Both unobtainium...
Great alternatives:
MANLAY SOUND Ronno Bender <------I'm gassing for one of these. He also does a based-on-on-an-idea-by That's based on the Mick Ronson tone w/o actually being a MkI TB called Aladdin
Ghost / Ian Sherwen
Skinpimp <----higher gain, more compression, less gated
Pigdog
Pretty sure Creepy Fingers has done some too
Who else? Montgomery maybe?
Depends how expensive is expensive?
[youtube]http://www.youtube.com/watch?v=NBMNpRLRh3M[/youtube]
[youtube]http://www.youtube.com/watch?v=IspJi9oZm4w[/youtube]