[penkia]

Because the boot loader is locked, so does its launcher, unless LauncherHijack installed and abuses Accessibility feature to draw Overlays on top of your screen....

Speaking of modifying existing hardwares, Nexus 7 is my personal favorite: http://i.imgur.com/8H9LH9U.jpg

[charlesju]

What projects do you need a tablet and you need it unlocked?

[penkia]

Anything related to flashing eMMC, anything kernel related, especially KMS/DRM, bionic libc... etc.

If you don't find it limited with locked device, you're simply not playing hard enough. :-))