While no GM-like UI is available, I've managed to get Stylish working on my tablet. It simply involves installing the plugin and the stylish.rdf file. I've included my file and simple instructions. I have 4 styles installed:

Gmail Redesigned (by Globex Designs)
Google Calendar Redesigned (by Globex Designs)
Google Web Search - dark gray redesign (vC)
Wikipedia - Grey Lady

Don't expect a stylish app from me, I don't program and am a linux noob. I'm just hoping this will prompt someone who does

Download stylish.rdf here. (sorry, couldn't upload here. if you run into problems, let me know)

Installation: assuming you saved stylish.rdf to your sd card, open X-terminal and type/paste in this (as user, not root)
Restart Microb twice. Enjoy.

p.s. I know my email is on the pic. I didn't want to bother to edit it.

EDIT: If you want to use your own styles, the stylish.rdf is found (in Vista) in C:\Users\Username\AppData\Roaming\Mozilla\Firefox\Profiles\*.defaul t