Today I finally gave up on repartitioning my USB disk and got forward in installing Debian to my NSLU2. So far it has been an interesting adventure. Initially I tried the stock firmware, which turned out to be poor for my needs. Then I tried unslung which turned out to be buggy in the configuration I wanted to create. So I turned to Debian/NSLU2 which is essentially Debian for NSLU2.
Installation is quite straight forward, there is a decent guide to work you through the initial installation. There are some interesting things in the installation, like the fact that you ssh in to the installation process, which was new to me. The installation itself takes a long while, but that is to be expected from a device with a low amount of memory and a slow CPU. So it might be time to leave it for the night and allow it to finish the installation in peace.
Oh! I have to say that even if I've said things about the current state of Debian, I still respect the project. It's not an easy thing to create an installer that works on such a wide range of devices and architectures.