Sweet! Old School LCD displays ROCK!
I can't really help you with the latest version of Winamp, sadly. Back in the day (V1.x) I wrote a program (which took the place of LCDC) to interface to a serial LCD. It took advantage of Winamps playlist (in limited form). I rewrote it a few years later and completely created a new playlist system (bypassed Winamps PL).
If I recall, LCDC can't do much more than script commands to Winamp - which means you're probably out of luck. If you can track down any specialized plugins which are written in C++, you might stand a chance. Winamp's website would be the best place to look.
Hope that helps. My old software is on my "old" website (check sig). It works quite well, but is rather alpha...