Yes and yes. Yes.

I don't know that you can develop .NET on the tablet, but you can definitely develop on PC, and run on tablet.
Perl, of course, is interpreted, so all you need is a text editor (your choice of emacs, vi, joe, pine, or a handful of graphical ones) and the perl interpreter.
And you can run apache or thttpd or probably one or two other web servers.

Python is very popular, it seems. And C, of course. Not much LISP going on, I'm afraid. Java (in the form of Jalimo) is about to some level of functionality; as I understand it, you could develop apps at this point and have them run, by avoiding non-implemented regions of GNU classpath. And tons of shell, awk, sed, etc. scripting, of course, just to stick stuff together in classic UNIX fashion.