Yes, chrome can be sandblasted off ... but it ain't easy. The majority of the cost in refinishing rims will be the prep for that very reason. Bad chrome in poor condition will blast off without too much trouble but good chrome in good condition will probably have to be ground off rather than blasted off.
As far as how shiney you can get with Powder Coating .... VERY. I've seen "Black Chrome" as one of the colors available.