Is it possible to rename the wp-admin folder?
I know I could just rename it, but unless it’s supported by the code lots of things would break.
If I use a custom folder name, it will make it slightly more secure, security by obscurity and all that.
If you’d really like to see this be revisited I’d suggest:
Present your case on wp-hackers but be forewarned your use-case better be good and not “security through obscurity” or it will get shot down as above.
Present your argument in a trac ticket with the same caveats.
Even better, upload a patch to trac that enables your desired functionality. It’s much harder to say no when the work has already been done (but of course, they do have a preference for saying “no” a lot more often than they say “yes” so be forewarned.)