Hey guys -there is a way to recolor walls and floors in simPE

If advaced mode is on in your simPE, you will find the walls and floors under "other" in the object workshop. CLone a maxis wall/floor (i don't knoe if it works for custom ones) and change the txtr files as you wish (like recoloring an object). The price can be set in XOBJ.
Look
here for a tut on this.