For processing I can definitely recommend Modernage (6th Ave in the 40s) for processing. They've done a lot of nice work for me in the past, and the owner is very involved with the lab and the customers.

I believe they also do printing on metallic paper. The last time I was there (couple months ago) they had samples of prints on it hanging in the customer service area. I haven't used that product myself, but their examples were very nice.