<<We Hackmaster players have come to know and love the d10,000. I've also seen it in Invasion of Arun'kid and I'm glad its making its transition into further KoK products. Kenzer came up with a really good way to have a huge random encounter list for each reason while still being able to scale it to the PCs level.
Long live the d10,000!>>
Lucius,
The d10000 roll actually originated with Kalamar (Gary Jackson stole the idea from us in 3rd ed. HackMaster). I don't think we ever actually published it in Kalamar (perhaps in Secret Temple of Adajy? -- my copy's at the office...), but we had some fairly extensive spreadsheets built around the concept (I hope these appear in the Atlas).
I got the idea from rolling random encounters out of Gary G's old 1e DMG. The tables were nested so you sometimes had to make several d100 rolls to get a result (roll up dragon, then dragon subtable to determine type, then age, then whether flying, etc.). I was annoyed and I thought the tables could be easily combined using basic math so one would need only make one roll to encounter a 'flying, young-adult, red dragon'. Mark Mueller (a shareholder and sometimes contributor -- he's also the rocket scientist (literally) that wrote the program to determine the phases of the three moons of Tellene (Kalamar)) created a massive 5 MB excel spreadsheet with random encounter tables for all of Svimohzia...it came out to be d10000. It's great because sometimes DMs need probabilities under 1% (like the chance of meeting a lich while traveling -- if you check for encounters 3 times per day you'd likely meet a vampire a little over once per month!).
Obviously, for HackMaster this was a natural.
David Kenzer