Clarifications: SM risers are 4" (recollection), & made of stainless.
Like the aluminum yokes, they can be polished if you get rid of the coating.
That's pretty labor intensive though, as stripper won't cut it.
I note there's a lot of enthusiasm for SM bars, drag bars, T bars on the BA & I like 'em too.
The lower (4") risers and straight riser sections in T bars are scarce to nonexistent, though.
These folks in NZ have been mentioned a couple of times as a possible source:
http://www.thehandlebarcompany.com/