the answer is, yes. linux 2.4.24 has working usb-audio 'class drivers', so if you've got a 1.1 usb-audio device around, just plug it in and use portaudio with a hint to udev .. not exactly JACK or ALSA, but certainly OSS ..
i've got MIDI going, incidentally, with usb-midi.o (class device) drivers .. MidiShare has been rocking the equinoxe.mid to a Virus all night, in fact, on the 'spare GP2X' ..