I'm happy to announce that my extensible BBCode module XBBCode is now ported to Drupal 7. I last worked on (and wrote about) this module in April while writing a new parsing engine for it.
Although the filter was working well, there were many small flaws in the surrounding management code that dealt with storing and editing custom tags and settings, interfaced with Drupal's filter API and handled the installation.
A recent core update to the filter module changed the numerical format IDs to textual names, which makes things lots more easier for automatically created text formats (namespaces, etc), so the required compatibility fix left the installation process far cleaner than it had been before.
Also, the actual tag packages, xbbcode_basic, xbbcode_list and xbbcode_table have been ported, so the module can actually be used beyond custom tags.
Unfortunately, while the Syntax Highlighter tie-in has been ported to Drupal 7, it is useless until the Highlighter module itself is ported. I cleaned it up for Drupal's CVS a few months ago, but it is still only compatible with Drupal 6.
Note that while the module can be installed and used without causing immediate major errors on a clean Drupal 7 install, it has not been exhaustively tested, and small bugs can still remain. It should not be used in production yet.
The release is available at http://ermarian.net/downloads/software/drupal/xbbcode/xbbcode-7.x-2.0.4-r496.tar.gz.
It can be checked out from SVN at http://svn.ermarian.net/drupal/modules/xbbcode/trunk/xbbcode.