Well, there is no GEQ available on Auxes 13 and 14... Anyway - the parametric equalizer should be more than enough to "color" what your sound guy wants to hear. Generally, it's not uncommon to use a mono or stereo aux solely for monitoring purposes. You don't need the Solo button. Just raise a fader (or several) and listen to the signal(s). This is also an easy way to check effect returns.

The call for a BIG tablet usually reflects the wish to be able to control as many faders as possible at once on all layers. As far as I know a BIG iPad can display up to 12 input channels, but I don't know how many faders fit on a Windows 21" touch tablet (if UC Surface is scalable). It's the nature of the beast that BIG and EXPENSIVE also means HEAVY and difficult to CARRY and HOLD, especially over a longer period of time. If you want it COMPACT and FAST, you might want to have a look at the DCA groups. Besides the fact that they also work on a SMALL and LIGHT and INEXPENSIVE tablet, DCA groups reduce the amount of faders drastically. You don't need more than 5 faders for a whole band, plus max. 4 for effect returns. "DCA Spill" allows direct approach to the input channels (including Solo and Mute) and by pressing only one button you're back to the DCA masters or the Main mix. The Mute buttons on the DCA faders are also nice, because you don't need to use the Mute Groups any more. DCA groups also have a Solo button, so what would you need more...?