What server is that popular for this to be needed? I usually just check back in a few minutes if it seems like fun, then give up after a few tries.
Edit: Maybe a waiting queue for a server - like, a box that remembers the servers you wanted to connect to. When there is room, and you are top on the list, it will give you a message-box-OK with the server name, host and an Accept / Decline option.
If this could work, even when you join another server, that'd be useful at least.
Edit2: lmao.
http://forum.blockland.us/index.php?topic=174208.0Sorry Slimabob.