Admin I/F Hacking?

I’ve read about modifying the Admin interface on previous versions of WP, but with the new filters and hooks it seems that you can do lots without changing any of the code base! Any pointers, articles, etc., on this? What I’m thinking about doing, based upon what I’ve read:

– change the Write/Publish page set based upon user level
– modify order of fields, look, entry of metafields.
– exposing certain category subtrees based upon user level, and updating other categories in the background based upon metafield entries
– mimicing different sorts of content entries, like blog entry, event entry, photo gallery entry
– a nice to have would be in-page edit instead of launching the Admin i/f. I know I could do this with the page template, didn’t know if there’s a slicker method.

Looks like this can be done, but I’d appreciate any pointers!

TIA, M.