Are you nuts?
You obviously don't understand how this framework is designed. This isn't even about web apps.
Where is there any hint that this will run untrusted? Since when does anything in Linux run untrusted?
Silverlight for great justice?
Isn't this the sort of thing Palm encouraging on their new Web OS SDK? Sadly, I do not believe there is a current option to write binary compiled code on that platform even if you wanted to. I'm happy with Maemo for now.
Linux is my primary OS and I use Hotmail only for legacy purposes every now and then since the account dates back to 1997. The new interface is essential to quickly remove all of the spam compared to the original version. It is still inferior to gmail.
I figured out this user agent issue months ago. Firefox Windows works, but any other user agent combination does not.
On the rare occasion that I check my hot male, I have to remember to switch the user agent and then switch it back.
There is a handy firefox plugin to help this called User Agent Switcher. http://chrispederick.com/work/user-agent-switcher/
Keep in mind that Firefox Windows is not a predefined choice so you must manually add an entry with the proper value.