I use an InFocus Kangaroo PC for my portable setup. It connects directly to my iPad which I use as a screen/input device. Nice add-in feature in the latest software allows me to connect directly from my iPad to the internal wireless eliminating the need for a cable. Main knock against it is that it doesn't have an internal fan so is somewhat prone to overheating if used in warm climes.
I've used it to run two instances of SGP (to control 2 DSLRs) plus a ZWO ASI178MM for autoguiding.
...Keith