I'm not sure whether it completely meets your requirements, but... most people use Rebirth 0.57.3/0.58.1 for online multiplayer stuff these days, and a lot of them use mouse (myself included, and even Jediluke, although last I remember he still missed joystick
). So I think it's safe to say it's not going to handicap you, although I can't promise it wouldn't take getting used to.
...though the netplay feels a little different now anyway - there is at least SOMETHING that might take some adjustment.
Edit: I just read the other threads and it seems there may be something config-wise that needs fixing to stop mouse control sucking... if it helps, most of the people on the DCL (including Jedi) hang out on the Rangers' voice chat server quite a lot, and someone might be able to help walk you through it. Copy-pasted from that website:
"Download Mumble here:
http://mumble.sourceforge.net/ then connect to server address mumble.descentrangers.com on port 31393."
I have to figure it'd be faster than tech-support-by-post/email. Oh, and while it is voice chat there is a text chat box, so you don't need to have a microphone. You also aren't required to be a Rangers member to join the server.