It's usually god's who debug in public, and where I am god, I usually debug on my special restricted little play node, where I do whatever crazy thing I want.
Your idea is logical, but not practical. Way too much overhead which a few gods could make obsolete by simply debugging stuff on their private nodes ... I wonder why they haven't done so already
(like when tye tested out his new ticker, it worked great for about a minute, but he, as a god, could've kept the rest of the pm out of the test) bad example, couldn't think of anything recent and applicable (this wasn't, so i don't know )
Anyway, the latest versions of everything2 have something like this kinda built in (there are "workspaces" to which nodes can belong to, and usually only one is accessible by regular users ~ like everyone except root), but that's besides the point (JavaJunkies is taking the e2 engine down, cause, well, of performance issues ~ probably related to the gigantic OO architecture of e2).
update: added stuff above, and below
as you know, pmdev'ers can only submit patches. only gods have the ability to actually change stuff on the server.
pmdev'ers should not rely upon the gods to catch syntaxt errors and such. I do miss the point sometimes (quite sometimes some might argue), and everything tye says below is true.