I'm a little puzzled here. Certainly I'm willing to dismiss the various Cerveny non-comp euphoniums (or barytons or Kaiser barytons, or whatever) as not being "of the highest professional standards", though I'm far from sure what criteria something has to meet to to be in that category.
But some time last year I came across an amazing euphonium performance on Youtube by a German musician, and when I tracked down his instrument it was a boutique brand (hand made, I think) non-comp euphonium (or baryton). Unfortunately, I don't remember the name of the company that made it, but I do recall visiting their web site and eyeballing the cost -- which was certainly of the highest professional standard. Whatever brand this was, they actually did have a catalog, and so the instruments were not one-off jobs. I might be able to pour through all of my emails for the past year and find this (since I sent a link to a few people). But does this ring a bell with anyone. For some reason, I'm thinking the price of this horn was in the $10,000 or above range.
Gary Merrill
Wessex EEb Bass tuba (DW 3XL or 2XL)
Mack Brass Compensating Euph (DE N106, Euph J, J9 euph)
Amati Oval Euph (DE 104, Euph J, J6 euph)
1924 Buescher 3-valve Eb tuba (with std US receiver), Kelly 25
Schiller American Heritage 7B clone bass trombone (DE LB K/K10/112/14 Lexan, Brass Ark MV50R)
1947 Olds "Standard" trombone (Olds #3)