Oh yeah, I've used the R-A-PS triangle before and have talked about it a lot with people. I'm surprised you and I haven't talked about it before. Other people I know of have made it a pyramid, adding a fourth point and making it a three dimensional chart, but the fourth point they use varies from person to person. I also recommend reading Bartle's work drawn from MUDs (http://www.mud.co.uk/richard/hcds.htm) as a lot of it can be applied to Larpers as well.

And glad to hear you had another fabulous run! Congrats!