I have been looking for a similar device, 4 mic inputs to record a string quartet, and bought a Focusrite Scarlett 18i8.  I haven't used it for recording yet but I did plug it into my Fedora 21 mini computer, started qjackctl and all the inputs and outputs were exposed.  It has 4 front panel mic inputs, 2 can be switched* to line, 48v phantom on each pair, 4 TRS balanced inputs in the back, S/PDIF in and out, and ADAT optical in for an additional 8 channels in, 2 balanced channels out on the back with 2 stereo (headphone) outs on the front, plus midi in and out.  It lists at $400 at several online retailers, I bought mine used on ebay.

There is an windows and mac mixer app, and you need to use the app to switch the two channels from mic/line to instrument and change other configurations.  Focusrite states that they don't guarantee Linux compatibility but they have published enough interface information that at least two programmers have created Scarlett Mixer python apps on Github, one is by Linux audio guru Robin Gareus.  With the program you can assign the headphone output as zero latency input monitoring or as output from your computer.

http://us.focusrite.com/usb-audio-interfaces/scarlett-18i8
https://github.com/x42/scarlettmixer
https://github.com/trrichard/ScarlettMixer

It seems to have solid stage worthy construction and a power supply with US, UK and Euro plugs.

-- Jeff Sandys