In case anyone is still following this thread, here's an updated version for the auto keyboard popup app in desktop mode. I basically took the versions that were posted earlier in this thread and updated to address some of the issues that I was experiencing.
This is again an AutoIT script (compiled version also attached), but with the following enhancements:
i. CPU resource usage fixed - it now takes less than 1% cpu on my system, as compared to the original version's 15%
ii. It does NOT require adminstrator access (I basically use a Windows POST MESSAGE function to hide the keyboard instead of killing it)
iii. It has a bit more logic in how it determines whether or not to show the keyboard, instead of just using I-Beam cursor. I found that I was getting too many false positives with I-Beam cursor alone, so instead I use a number of different approaches depending on the underlying active application, including specific detection modes for browsers, for Excel cell editing, and then by trapping Window's own BlinkingCursor message. If all this fails, we fallback to the original I-Beam trap.
1. Just copy the "Desktop Keyboard.exe" and the Resources folder somewhere convenient, and put a shortcut to the .exe file in your startup folder.
Its still not perfect, but for my own needs (on a Surface Pro 2), it is about as good as it gets without something that is more tightly integrated into the OS. Hope it helps other tablet users!
EDIT: Please note that the compiled version included was built on an x64 version of Windows 8.1 and also x64 version of AutoIT 18.104.22.168. If you get a platform error, it could be because you are on 32 bit Windows, in which you would need to recompile in AutoIT.