I'm looking for a project management system for Emacs

[Marcin Borkowski]

Hello all,

as stated in the subject line, I'm looking for a project management
system in Emacs.  Since there are quite a few of them, I thought I
could ask here.  I don't have /strict/ requirements, but rather a few
problems I'd like that system to address, and a few features I'd
probably need.

1. When I have many files open, switching to another buffer is a bit
cumbersome, even when using Ido.  I'd like that system to have
something like "ido-switch-buffer-within-project".

2. Files of the project might not be located in one folder (so
e.g. Projectile probably won't work for me).  Rationale: there may be
a few files somehere down the ~/Documents hierarchy and /one/ file in
~/org.  On the other hand, I'd like to be able to specify that "this
file and all files in that directory belong to this project", without
manually listing all the files in "that directory".  It would then be
best if adding a file into the specified directory (or tree) would add
it /automatically/ to the project.

3. One file may belong to more than one project.  Rationale: see above.

4. It would be great if I could mark some /global/ variables
project-dependent, i.e., each variable would have its "project
instance", and switching between projects would mean changing its
value accordingly.  (It would probably also need some kind of
persistence, too.)  Rationale: org-clock-history;).

5. Of course, I'd like to be able to visit/kill all files/buffers
related to the project with one command.  Also, adding a project (and
a file/files to an existing project) should be possible in some
interactive way (though using some Elisp variable for that might be
acceptable).

6. On the other hand, window configuration management is not a must
for me - currently I work 98% of the time on a small netbook and
usually have only one window open anyway.  I'm planning to use a
larger monitor in some time, though, so while not necessary, this
would be a nice bonus.

Is there anything in existence that would help me?  Are there any
potentially useful features I did not think of that people find
useful?

TIA,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Adam Mickiewicz University