Mod request - one more slot

[Keneth]

Short answer: No.
Long answer: Noooooooooooooooooooooooooooooooooooooooooooooooo.

Actually I'm not completely sure, you probably don't have access to the required code, but even if possible I imagine it would require a lot of code editing as well as a redesign of the interface. Not to mention it would be monumentally imballanced, the game is easy enough as it is.