It's done. Got minibb2.0RC1f live, up and running. It tooks me 3 hours to migrate from 1.7. I've used an alternativ migration path: installed from scratch on a test instance, made all my changes, migrated the DB, testing, made a DB backup, renamed the production directory, copied over the new directory, ran upgrade and conversion scripts against DB, changed the rss part and - it works.
Ok, this way is applicable if you have not too much touched in standard code. But was cleaner then hacking all the templates (tried this before and result was a scrambled layout ;-)
Let me say thanks at this point for your great work and effort.
If you want to have a look at the new version: http://www.copypolice.de/forum/
(main audience is german, so it might be hard to read)