To be exact the topic should be only telnet to eggdrop using tcl / xchat without irc. I added dcc chat in brackets because it's more known then telnet. Telnet has almost the same features as dcc chat but I always found telnet to be less comfortable.
Telnet is always useful if the bot won't come to irc, to see whats up. No irc connection needed. Just set the listen port inside the eggdrop configuration. An advantage of telnet is that it does not need any port forwarding on client side.
There is no more need to use ugly telnet clients. Windows 7 doesn't even have one by default installation and you are typing blindly, copy & paste is uncomfortable, colours are not supported and also notifications (blink on new message) are not available.
I was always looking, goggling and thinking about alternatives.
Telnet isn't must magic. Actually the implementation is quite simple. Look at http://www.scriptkitties.com/tclplugin/ and download Example Tcl Plugin Scripts. Inside the archive is a telnet.tcl. I had to change all 'print $::telnettab "$..."' to puts $..., dunno why, but that's xchat related and I will learn that later.
It's a little slow, but sufficient, copy/paste/notifications do work and even colours aren't distorted.
If you have trouble setting this up, I'd recommend the login in shell and to 'telnet localhost listenport' to see if telnet does work before you think about implementing it in tcl.
It's not limited to xchat, there are other clients with tcl support, but I am using xchat for now, because then I do have no need to develop a gui and all can be nicely integrated into the irc client.
This isn't news but also nothing what can be already found in the forums.