So i just created a gamemode using this. It's kinda like speedkart, but it's not.
Here's some links:
Gamemode_Jumpman - the gamemode
Jumpman_Pyramid - jumpman_ add-on, these are kinda like the speedkart_ prefix add-ons
Jumpman_Golden_Gate_Bridge - jumpman_ add-on, these are kinda like the speedkart_ prefix add-ons
I'm also in the middle of making a platforming-like level.
If people like this gamemode, I'll release it formally.
Also the gamemode will work by itself, the playertype and a few other things are packaged into the gamemode. You still need a Jumpman_ prefix add-on, though.