DON'T READ THIS POST. SOLUTION IN 2ND POST.
I know it was tried out a couple years back but was given up because people dislike it. There are many pros to IRC. Mobile IRC clients so you can connect and talk from anywhere as long as you have web access (you don't need flash). You can use both the web client and the normal client. There is a topic and there is no cap for typing. It'll be slipt up into multiple messages if there is one. There is really no reason not to use it. It's pretty easy to setup also.
Last time I believe people were complaining about the join/part messages well it's hidden. The UI is pretty simple however. There is also another web IRC client that you could could use.
<iframe src="http://chat.efnet.org:9090/?channels=raptors&uio=Mj10cnVlJjk9dHJ1ZSYxMD10cnVlJjExPTIwNQ0f" width="647" height="400"></iframe>
You can mess around with the client here, check out the themes and iframe generate code here
It's has a lot more polish to it and could be used to replace this proprietary chat that is currently on the site. It has smilies (even though IRC doesn't support them, it'll change the code to the emoticon). There is also some custom theme support. You could download it and upload it to your own server and host it there or use the icode.
I really think you guys should give the second one a shot. There is really nothing wrong with it. It's still flash, it still easy to install and use, it looks nice but it also has the perk of using mobile or desktop IRC client and IRC features.
<iframe src="http://lightirc.com/start/?host=irc.paraphysics.net&autojoin=%23raptors&showNickSelection=true&showServerWindow=false&styleURL=css%2Flightblue.css&nick=User_%25" style="width:800px; height:400px;"></iframe>
Edit: Lightirc needs flash policy server so you guys would have to create a new channel on a server that supports it and can't use #raptors on efnet so no nba bot. There is still the first client but even if you want to use the 2nd client without the bot it'd still be better than the client right now.