This sounds great. It is amazing that so many things are already anticipated in LuaJIT architecture.
I must confess I thought once about using NaNs as a technique of handling dynamic types in scripting languages, then I found LuaJIT and surprisingly it was already there implemented and running.
Looking at all the innovative techniques used in LuaJIT I think all your work deserve great respect from world-wide community and spreading the news so also other languages such as Ruby (which I use everyday) or Python adopt these inventions.