OK, as far as I am concerned, TBNL is hereby deprecated. If someone else wants to inherit and maintain it, they should contact me.
I think that the current release of Hunchentoot (modulo errors) is a worthy successor/replacement for all implementations supported by TBNL. In particular, I expect less issues with SBCL due to the use of FLEXI-STREAMS.
Please download, install, play with it, and report problems to the list:
http://weitz.de/files/hunchentoot.tar.gz
Note that some parts of the API have been slightly changed. Consult the docs if in doubt. And if you find mistakes in the documentation, please report them as well.
Have fun, Edi.