have you checked out the logitech ps3 mediaboard? http://www.amazon.com/Logitech-PlayStat ... B000W5RBQE
it has a nonstandard key layout (there's a mouse-left/mouse-right click button where the start button would normally be, and the media keys are mapped to random letters), but it's decent to type on and it's pretty much the size of a regular 101-key keyboard. i used it a lot when i had a computer hooked up to my TV - it pairs like any other bluetooth keyboard.
macally makes a range of bluetooth keyboards (among other items) - i can't vouch for their products personally but they're fairly well-regarded as far as 3rd party mac accessories go. here's one that might fit the bill: http://www.amazon.com/Macally-BTKey-Wir ... h+keyboard
. I think that the start/command key maps to the home button on android, but it's been a while since i sold my nexus 7 so i don't remember exactly.
I can vouch that the amazonbasics bluetooth keyboards work with pretty much every tablet/phone i tried them on: http://www.amazon.com/AmazonBasics-Blue ... B005EOWBKE
but i don't know if that's quite large enough for your needs. they make an android-specific version as well.
Apparently USB keyboards work with the Nexus 7. Personally I think it'd be hilarious to use a USB Model M with it.
that's another option. USB on-the-go adapters for the nexus 7 are fairly cheap, and from what I've seen on google it's just a matter of finding a USB keyboard that doesn't draw too much current from the USB port. they're also handy for attaching USB thumb drives, if you need more space.