A few BMW bikes. Good luck sourcing a pair that way-very rarely available in my experience. I think the R80G/S had one 48mm front caliper as standard and a second was an option.
According to some parts suppliers, the following bikes also used 48mm Brembo (I'm unsure which ones used r/h and l/h as a pair though) R65, R65RT, R80, R80GS, R80GS PD,R8ORT, R100GS, R100GS PD from 1987 - 1996. I was only aware of the GS fitment as a pair. The 48mm P9 calipers are very heavy lumps - unless you need them for originality I wouldn't bother. Twin pots are much better!