As for toddle.c my suggestion would be to use one color to draw the toddle oval and another to draw a bang. It is perfectly possible one would need a panel with quite a lot of toddle-buttons and would want to differentiate them with colors.
Unfortunately this second modification would corrupt all of the Pd patches currently using toddles, since it would require having two symbol arguments to toddles in .pd files instead of only one. Therefore this needs a broad consent among the users or some witty upgrading solution.
why, why ?
since the normal background-colour would be only optional, it would be the second symbol argument that defines the colour. eg "toddle blue" would do a normal toddle that get's blue when banged and "toddle blue red" would get a red toddle, getting blue when banged.
or check whether there are 1 or 2 symbol arguments: "toddle blue" would do a normal... "toddle blue red" would get a blue toddle, getting red when banged
no problem ?
mfg.asd.gtr iohannes