1. a special ignore list (that affects only the tree), so I could 'ignore' the A:\ drive altogether or some sub-folder
Just use TweakUI for that... You can hide drives under
My Computer -> Drives.
2. ability to specify a number of virtual folders to appear at the same level with the drives.
This is shell specific stuff. There is a power toy for doing that, the Shell Object Editor:
http://www.tropictech.de/modules/PDdownloads/singlefile.php?cid=1&lid=5
After starting, just activate the Expert mode (rightclick), then you can for example move
My Documents to
My Computer.
If you are using XP, don't do that, instead use TweakUI and activate
Files stored on this computer under
My Computer. Otherwise Explorer and TC may crash as soon as you expand
My Computer. I don't know why, though...
No matter what, do backups before playing with the editor! If something goes wrong, you have to edit the registry to fix errors and if you have no clue you will run into problems. You have been warned!
Icfu