sorry, theres no such thing as an mIRCd. There are ircd's written in mIRC script but they are flakey at best.
As for IRCd's, whats wrong with linking another unrealircd server to it? Servers link together to make a network, and both/all servers need to have their config file edited correctly to allow this.
this all came off of the other post i had about a program that will link my computer to my server, i found out about mIRCd's, and i was trying to find one that could link to unreal, but i finally got ahold of my friend that made that program i was talking about, he's gonna change it so its like an admin panel, where you have full control over the server through it, i told him make it so you can configure what server you connect to, and the linking passwords and stuff.