Been working on this for a couple of days now, it seems at this point in time the keyboard and numerical keypad are un-changeable even if its just a color swap let alone actual edit. As for the background of the home screen, it seems that it is color code that very well could be hard coded into almost how bootloaders are on motos. We have a pretty decent discussion about this over at modmyiPhone.
Also we might have to wait for another program besides iPhoneinterface to come out or perhaps an update to it, because all the images are not viewable in that program nor are any of the animations, in iPhoneinterface you can only view/edit one animation and it is a .mov file - hope this helps some people