So here she is, Rubber Mouse as designed and colored by Inkwell based on my fairly sparse description. A direct link to the original art will go up once the artist posts her to his Tumblr can be found here. If you like the look, please do consider commissioning him!
The pink outfit is pretty much her standard outfit. The yellow is her dress outfit for special occasions. As for the blue, so far it has no specific explanation, but perhaps that will come in time.
Don't get used to seeing her like this though. This girl is rather danger-prone, so she spends more time on the losing end of battles than most heroines.