I can give you...

A paternal cousin of Carmelina Cramming? The Warbecks are Welsh, black, and MCHB, but if Carm's dad had an elder brother who was the ~first son his branch could always have been a little stricter/more ambitious than Cedric's side and arranged marriages etc! Or could have been financially struggling, whatever.

(Otherwise I have @"Jemima Farley" but the rest of the extended Farley fam are purist so probably wouldn't have been arranging marriages for their kids to halfbloods.)