If you are on windows, the PostGIS 2.1 window binary builds get built whenever there is a change in PostGIS 2.1 code base by Winnie our windows PostGIS build bot, for PostgreSQL 9.0-9.2 (64-bit) and 9.2 (32-bit), so you can't use the I can't compile excuse if you are on windows, not to test out the new changes :). You can download these from Windows Experimental Builds. We are hoping to do the same for Debian Squeeze (6) soon. The main reason we built our bot Debbie on Debian (which makes the source tarballs), is because Debian is a very popular deployment platform for PostGIS, that is currently underserved so we have many Debian users frustrated at not having a readily available PostGIS 2.0 release for example.
I too am both a Debian and PostGIS user and am frustrated by the lack of a PostGIS 2.0 package.
I have made several attempts and updating it (work is kept at http://anonscm.debian.org/gitweb/?p=pkg-grass/postgis.git).
A lot of the challenges that we face are patching the upstream build system to work in the Debian environment.
For instance I've had to patch the build system at postgis/extensions/postgis/Makefile.in to make the sql directory at build time (because these directories are empty in the source tarball and somewhere the process of importing this upstream tarball, the empty directories were lost).
Also in postgis/java/jdbc/build.xml the default upstream build will try to pull dependencies over the Internet. This is not allowed in Debian for good reason, so we need to undertake work to patch this so it shall use the local libraries.
The problem I see is you need someone with skills that intersect. ie. someone skilled at debian packaging AND skilled with the Maven build system. If someone knows how best to do this, then please open a bug report at bugs.debian.org and provide your patch. It won't be packaged unless we have people come forward and help out.