One of the problems then is you'd lose the flexibility of where you put your PAW, as it would have to be mounted with the AHRS flat and in line with the aircraft's longitudinal axis.
My personal opinion is that, while these add-ons are fantastic gadgets, the PAW is meant to be a box to assist us in avoiding traffic. There are already suggestions that it should have ADSB out and UAT weather incorporated but an AHRS drives the purpose of PAW in a different direction again (do you see what I did there
). After AHRS there will be a call for a pitot/static input and, in that case, you'd be far better off with one of the boxes specifically designed to provide your tablet with an EFIS e.g:
http://www.wheelsandwings.net/talos-avionics.html