I'm thinking you can pretty much grind or sand whatever area you want to whatever profile you want without too much problem. I remember when the reg/de-reg first came out and Dan said that the mill marks on the de-regs could be smoothed out with sandpaper i think.
I have thought about doing it with one of mine and was just going to use a disc and or belt sander with whatever grits seemed to work best. Possibly even my 4" grinder or dremel.