I was going to mention the "Celtic" strings have even-time 3/4 sets, but you're right, they're all trios at best, no quartets! shocked
Ok, so perhaps you could sort of fake it by adding a Cello or bowed bass for the bottom instrument, but it wouldn't be quite the same as a set that's designed as a quartet section from the get go. Besides, we need sets for the classical genre as it is, and your request could fit right into that.

+1


Just because you can, doesn't mean you should!
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