Does "defaults read org.x.X11" say anything regarding the port number? If so, have you tried setting it to 6000 using the corresponding "defaults write" command (possibly requiring sudo)?
Nope, and note that I'm "special" yet again - I'm using the MacPorts X11-dev (that is, pretty much always the newest version.)
defaults read org.macports.X11 does give me a list with a lot of options, but only those which could be set via the GUI too (rootless, clipboard, etc.) - no displayPort or TCP port.
AFAIK the X server is autodetecting the displayPort and adding this to 6000 (i.e., port = 6000 + displayPort = 6000 if displayPort == 0).
At the same time, I really don't see any reason for connecting to the local machine via X11, I'll try to get a connection via the UNIX socket during next week. :)
I fetched both and will give them a try once my Mac is back. ;-) Note that my Mac is x86_64-based, so I will neither be able to confirm nor to deny the functionality of the x86 support. Well... personally, I don't care about x86-only machines either, as there was only one generation without x86_64 support, but since I "went the extra mile", I'd still like to know if it's working on these boxes too. Let's see if other people are reporting back. :)
Best regards,
Mihai