You probably want to look at Susato's "Danserye" for crumhorn-quartet music.

Something utterly different: you might look at music for Armenian duduk groups. There is a lot of solo duduk sheet music available free on-line, but not the trio and quartet arrangements, as far as as I know. Mostly there isn't much to the arrangements - added drones and pedals, even simpler than Susato - and you should be able to work it out for yourselves. The range and scale of the duduk and crumhorn are similar, but the tone is utterly different, so some pieces will work and some very definitely won't. Duduk music tends to the sombre and melancholy end of the emotional spectrum, totally unlike what early music groups usually do with crumhorns, so if you do it right it could be effective simply because it'll confound expectations.