Buying a device and controller doesn't work so well. Gaming battery life is significantly worse with a tablet, the Shield's batter life alone makes it worthwhile. There is input lag with bluetooth. Gaming clips or attachments are also very clunky.
A Dreamcast emulator would make the Shield perfect either that or Sega ports Dreamcast games to Android (possible but not likely). Need my dosage of sonic adventure. I see no reason why the Shield Couldn't run a dreamcast Emulator flawlessly. Hopefully Nuldce is completed or Lxdream is ported...
If you need a physical keyboard so bad there are options available like this http://www.amazon.com/FE01-BL-Wireless-Keyboard-Mouse-Touchpad/dp/B003UE52ME/ref=sr_1_2?ie=UTF8&qid=1377704300&sr=8-2&keywords=mini+bluetooth+keyboard and...
https://play.google.com/store/apps/details?id=com.n0n3m4.QIII4A
Try this version out when you get the chance. The older Kwaak3 is no longer in development.
Could someone try Openbor on the Nvidia Shield?
Download Links
https://www.dropbox.com/sh/gv17zu4f5...ZqByz/releases
Compatible Mods
http://dl.openhandhelds.org/cgi-bin/gp32.cgi?0,0,0,0,11
Running on a JXD
https://www.youtube.com/watch?v=cBKDGblkaQw
Snesfan or anyone else who owns an Nvidia Shield could you try out Quake 3 For Android?
https://play.google.com/store/apps/details?id=com.n0n3m4.QIII4A
It has been optimized for controllers and one of reviewers say it work with an Nvidia Shield and someone got it running on an Ouya.