I use a Zoom H4 as an audio device via a USB adaptor (i.e. "The camera connection kit") on my iPad mini. That give me a bunch of audio IO (including two phantom powered XLR connectors), latency isn't brillaint, but the audio recording software is pretty good and allows for building demos with quite a lot of usable preproduction work!
-edit- sorry, just realised that you arena talking about a Win8 tablet. As long as you avoid the WinRT ones, you can use all your Windows software and hardware... Though for the money, a cheap generic laptop might be better
