Don't most keyloggers also log mouse clicks, along with their location?
I've seen UI's where the keyboard/number pad has the location of the characters randomized, which looked like a good way of solving that problem.
I've seen randomized images bypassed by simply taking a screenshot in conjunction with logging keyboard and mouse actions.
Yes, quite often the "On Left Click" action is tied to a "Take Screenshot" function, useful for defeating these types of on-screen keyboards, randomized or not.
That seems like it would take up a lot of space/bandwidth, but I suppose that it's 2012 and it's trivial.