[rrhm]

Perhaps "plutocracy" would work. The root "ploutus" is the ancient greek word for "wealth".

[toyg]

Yeah, but that has already assumed negative connotations; you cannot use it for tongue-in-cheek jokes.

[georgecmu]

leptocracy: lepton[] + cracy

is exactly what you want and is an easy allusion to kleptocracy.

[] http://en.wikipedia.org/wiki/Greek_lepton