Yeah, that subclassing code used in the okSocket is interesting. Assembly stuff I guess. I don't really understand how it works either. The hardcores like Paul Canton (the guy who wrote the subclassing code) do and that works for me.
For some other nice (hardcore type) stuff you should check out some controls from planet source code, esp the stuff from Charles PV. All API and very easy to use. Cool things like toolbars, status bars, list view, even an .ico editor and a couple games!
Linkage!
For the split times/on-screen stuff, the easiest way would be the rcm messages like you said. Just do a couple InSim.SendMessage lines and thats all it takes. And a timer control could clear it after 5 seconds or so.
I have thought about trying to figure out the DirectX API to make stuff appear on the LFS screen but have been kinda busy lately. Gotta update the Layout Thingy too.