[LAU] Looking for a mixer, 16+ channels

Hi guys (and gals), a good friend of mine is in the market for a mixer that is at least capable of recording a whole band simultaneously. He thinks that 16 channels might be a minimum for that, but he isn't exactly experienced, and me neither. It would be nice if it would work as firewire audio interface as well, like the mackie onyx mixers, mainly because it might mean less trouble overall. Those onyx mixers look nice, and are supported by ffado, but we'd like to have some more options. Linux support isn't a strict requirement but it would be really nice to have as option. So far it didn't work for him, but when the hardware works with linux I can show him what's there and what's new from time to time. In this case he has a budget of up to 3000 Euros or possibly more, but the stuff really needs to work for a studio. Thanks in advance for any advice, best regards Philipp