Hey!
mIRC by default shows the topic or a part of it on the top of the window!
Without colours though. If you haven't seen this you might have turned it off by accident. I think it is in the display menu but not sure.
If you have seen this and don't like it.. i dont think it's easy to make that without the use of a DLL. The A toolbar script could be used without any buttons and the topic would be /drawtext in a window, saved.
I think that's a good solution! But.. i'm not able to make itnow and i dont know if it's completely doable!