I have a Deneb in my A4000, using keyboard, mouse, soundcard and SD card reader. The keyboard and mouse are actually a wireless PS/2 combo connected to an off-the-shelf USB->keyboard&mouse cable, and the soundcard is the first one I could find in the local cheap computer stuff shop, and supports 16-bit 44KHz audio no problem, but you may struggle with the speed with a 68030. As they only cost a tenner or so, though, you may as well try!
