If you really really want it that bad, start digging through the linux source code, so you can see the mess for yourself.
I'm not trying to roadblock your ingenuity here, but you need to understand what you're suggesting before you suggest it... know what i mean?
Two options:
1) Port mozilla, re-writing all low-level rendering code to D3D routines... lots of work
2) Currently, you must boot a full linux kernel. Build a stripped-down linux kernel for the xbox, which loads nothing but the requirements for web surfing. Well, you want to maintain full driver support, but somehow *remove* all security. You want to support some hardware, but you don't want to worry about the unecessary hardware. This, but not that... this, but not that, etc.... oh, and it has to work =]
Get my drift? It's kind of a bitch.
here's the question to ask yourself. Do either of the above tasks seem practical when you can already surf the web on your box? You can... it just takes a while. Is the speed increase worth months of work? if you say Yes, that's good, I'm glad someone feels that way. But most programmers are quite busy, so keep an eye out for one that's interested in investing the time.
Take care all