For anyone that's still looking for a pop-up keyboard solution in desktop mode, I've posted an updated version to the previous versions that were floating around over at the XDA forum (xda-developers - View Single Post - [MOD REQUEST] Auto popup keyboard on desktop). It basically addresses the resource usage issue, does not require admin access/UAC permissions, and has a slightly better text entry detection mechanism.
Hope it helps other Surface users!
Hope it helps other Surface users!