Plotting to a matrix

Hi

I'm trying to find out if anyone has heard of a function which can be used to makes plots (e.g. line plots, scatter plots, bar charts) in a matrix such that they can then be displayed as an image. I'm aware of the "getframe" etc which can be used to grab plots made using the standard matlab graphing functions but I'd like to be able to make small low resolution plots directly into matrices (~50 x 50 pix for example) in realtime (60Hz) and superimpose them over images being displayed using the psychtoolbox libraries.

I can imagine how to write this myself but I thought I'd ask before reinventing the wheel.

Any pointers much appreciated!

Adam