In December (2005) I started work on a plugin for the jEdit editor to allow it to edit TYPO3's setup and constants "templates". It's out in beta now, available from jEdit's plugin repository as "TypoScript" and the server-side component "jeditvfs" from TYPO3's extension manager.
This is what it looks like:
As you can see, it supports multiple sites, and as of version 0.1.1, it handles multiple templates on the same page.
For users of TYPO3, I think an external TypoScript editor like this in invaluable, considering we're normally confined to a textarea in the backend, and every save causes the script to jump back to the top. You often find yourself doing a lot of guess and check, which is a real pain in the backend. I used to just copy the template out into jEdit (before it had syntax highlighting for typoscript, also courtesy of me), edit it, then paste it back into the backend to save it.
Documentation for the client can be found here, and documentation for the TYPO3 extension can be found online here or in OpenOffice format here.
If you're a TYPO3 person that works with lots of TypoScript, please try it out! Email me with any bug reports or feature requests.
The plugin and extension are both licensed under GPL, the source is available from jEdit's public CVS and TYPO3's extension manager.
