1.) opie-doctab is the settings application that allows to disable the doctab functionality.
2.) When I added the possibility to disable the doctab functionality I also looked for ways to hide it completely. After fiddling for two days, I couldn't do that without destabilizing the launcher, so I gave up. Patches appreciated
3.) We would embrace any better alternative, but we don't have one. We would like to have a SharpROM 3.x fileview or just opie-advancedfm in the doctab, but there haven't been any patches coming in for that.