Newbie Q: Can I put all my XUL App in ~/.mozilla

I want to know if I can place all of my app under my ~/ directory.  I 
would prefer to put all my development code in something like ~/code and 
then point to it with one reference in my user profile.  What I've read 
on this subject so far tells me to go in and hack on stuff in 
/usr/local/mozilla. Ideally, all apps should have the option of 
installing under either the user's home directory, or under the system 
installation directory.  I see that is being discussed elsewhere, and it 
is beyond the scope of my current problem.

I simply want to know if I can do all of my development and testing 
under my ~/, and if so, how.

<soapbox>
It is a gainst my religion to login as root unless I am specifically 
modifying something at the OS level. Not only that, since I typically 
install each nightly, all my stuff get's blown away on a daily basis. 
And to make matters worse, I can't seem to get the nightly build 
xpinstaller to change the installation directory to my user space.  I'll 
deal with that elsewhere.
</soapbox>