A compact carriable MFD tethering solution for using in the field is an interesting aspect for many of us tech cam users. It's easier to understand a composition when you see it on a large screen.
For me personally I'd love a compact portable solution to circumvent the really bad screens of most legacy backs (the only backs I can afford) where you can't even check sharpness, which do me is a desirable feature. However as the helpful responders above pointed out it's not possible as the legacy backs have firewire and Surface Pros don't, and there is no working converter on the market.
I don't find Macs being a good solution for me, much too fragile for the type of hiking and various weather conditions I do. The Surface Pro is probably to fragile too, but there's a lot more likely to find robuster units in the Windows world than in the Mac world, but firewire is kind of dead for PCs :-\. So what I'm looking at is staying with the Aptus series for the time being which is the only legacy back that has working sharpness check.