Hello,
I have a Vox ToneLab EX guitar pedal, which can be used also as a sound card. This is already almost supported, it's enough to add the following to sound/usb/quirks-table.h, immediately after the analogous entry for the ToneLab ST which is already there:

{
	USB_DEVICE_VENDOR_SPEC(0x0944, 0x0204),
	.driver_info = (unsigned long) & (const struct snd_usb_audio_quirk) {
		.vendor_name = "KORG, Inc.",
		/* .product_name = "ToneLab EX", */
		.ifnum = 3,
		.type = QUIRK_MIDI_STANDARD_INTERFACE,
	}
},


So far I have been manually patching my kernel, but I think this could go upsream...

Thanks!