has anyone thought of just having a bunch of cloud servers with LaTeX built there, and then writing a front-end which uploads your docs, compiles them and downloads the resulting PDF? with fast enough servers and good enough data speeds, this might even rival the estimated 10 seconds for a fully ported LaTeX app.
I'm assuming it's been ruled out for other reasons though.
EDIT: this would also make it trivial to use it on android/blackberry, without any extra effort. apparently, also, http://www.scribtex.com/
At ScribTeX we regularly get comments from users about how fast our compiling is. Even with the round trip to the server, the PDF appears in the user's browser quicker than if they compile it locally. This isn't due to anything especially clever that we've done but instead stands as a testament to data speeds, and the performance of the Linodes that we compile on. Particularly with Linode, I think the high disk IO performance makes for a very quick LaTeX compile.
I wouldn't sasume it has been ruled out - people (myself included) sometimes get mentally stuck on one solution and fail to spot another obvious avenue.
I'm assuming it's been ruled out for other reasons though.
EDIT: this would also make it trivial to use it on android/blackberry, without any extra effort. apparently, also, http://www.scribtex.com/