Changing neck profile?

I have a really nice parts bass with an Allparts TBRO rosewood tele bass neck. Super chunky and I'm wondering if a luthier can change that shape from what feels like a U shape to a modern C shape. Allparts specs say its .89 at the 1st fret and .99 at the 12th fret. I think a modern C is about .79 and .99. It's the square heel shape so I have been unable to find a slim replacement neck with the tele headstock and the square heel shape. Any suggestions?