Daily installer images are now available for the QNAP TS-109, TS-209 and TS-409. This means that complete installations of Debian testing are possible now.
You can consider the daily image as a beta release of RC1 of the debian-installer for Debian lenny. It should only be used by experienced users and only if you can make a serial console in case something goes wrong. As the name suggests, the daily images change on a daily basis and they install Debian testing which also changes on a daily basis (although testing should be fairly stable since we're close to the freeze of testing in preparation for the release of Debian lenny).
If you install Debian with these installer images, please send an installation report to debian-boot send an email to me so I can let you know in case there are any important news you should be aware of.
There is a web site now with complete installation instructions and other information about Debian on QNAP Turbo Station. If you have any questions or suggestions, please let me know.