I compiled Squeak-3.0 from sources on Linux, and I didn't have to be
"root".  I would expect things to work no differently on
other versions of UNIX.

I compiled it as follows.  I untarred the distribution and cd'ed into it.
Then I created "build/unix", cd'ed into that and ran
"../../src/configure", followed by "make".  

That is a bit unusual; people expect to be able to type "./configure;
make", but it isn't a big show stopper.  I think it would be a good
thing to fix, though.

Once you have an executable, you give it an image file on the command
line and have the corresponding changes and sources in the same directory;
it doesn't seem to care otherwise how or where or as who it was compiled.
You should be able to write a two-line shell script to start up whatever
VM/image combination you want in whatever directory you like.

Cheers,
Thomas.