For chroming metal parts I'd suggest calling your local hot rod clubs
or antique auto clubs.  Car freaks spend a lot of their time having
chrome work replated and would know the best people to hire.

Plating does require a number of stages of work, however; it's not just
dip it and go.  My maternal grandfather was a electro-plater and had
his own company, but it went under in the Great Depression.

Krylon Paints make a aerosol spray paint that is very realistic, in
shiny gold, silver and copper, etc.  It's sold at Canadian Tire stores
here in Canada and I assume most paint or hardware stores in other
places would carry it.  I'd suggest trying that on plastic.

Nelson Denton