As was suggested you an send them out to be chrome plated, which usually runs big bucks, but not always. there is a company called Chrometech USA, that specializes in chroming model parts. They aren't that expensive, just keep in mind, that the part has to be perfect.
Aside from that it is possible to chrome plate at home. The standard electroplating is possible on plastic, but there is some preperation involved. There is an electroreactive spray designed specifically to be sprayed onto plastic to allow electroplating.
While alcad looks good, to me it looks like either polished aluminum or dark chrome plating, instead of light chrome or show chrome. Actual plating is going to be the only way to go if you want the real deal look.