mmcc,
René Spada (
www.spadamusic.ch) has a shop in a small Swiss village near Bern and has specialized, for many years, in disassembling trumpets ordered from Elkhart (a brand which will remain nameless as I don't want to engage in the sort of trumpet bashing that can be found elsewhere online. Let's simply say a great design that often suffers from mass production?) and finishing them properly by hand.
He converts many of these custom trumpets (my horn in question happens to be a Bach valve section with a Blackburn bell and leadpipe/tuning bow) into tuning bells.
Jouko Harjanne has played René 's trumpets for years, as do many other European soloists (Giuliano Sommerhalder pops quickly to mind -- boy, there's a talent)
Best,
EC