Run a VPN server on PlayBook ?

How feasible is the idea of using an old PB, which is currently sitting around collecting dust, as a home VPN server (even just for simple PPTP)? I'm talking about 1 or 2 connections at a time at most, does the PB have enough processing power to handle this? Given its small footprint, quiet operation, and low power consumption (it would obviously be plugged in 24/7), it would be pretty sweet.

I know this isn't possible out of the box, but... perhaps it could be via an app?

For sure you would need an app! In theory it could work.