I'm thinking 6" is the ideal size. No, it can't be a windows phone. It has to be a tablet running either windows rt 8.1 or windows 8.1. I've been working on an LOB app for our engineers. Field testing it with the surface is ok, but the surface is still a little big for field work. I just got an idea that we could strap a small tablet on the forearm so our engineers could be hands free. An 8" tablet is ok, I suppose. I've already submitted a proposal for my company to buy me an 8" tablet (the lenovo miix 2) for me to do some field tests. But I'd rather have a slightly smaller tablet than 8". Please help.