The $285.00 Stainless

from Cobra Accessories is really, really nice. It comes unwelded, but the downtube is already machined. I took it to Fast Eddies and he laid a gorgeous bead on it for $40.00. I didn't want to grind the welds because that would be like grinding the smile of Mona Lisa (or the jugs off Pam A.).
Don't worry about SCCA rules - a Cobra hoop isn't close to legal for lots of other reasons.
Good luck