You might try Fordham Marble, originally from The Bronx, but now in Fairfield County, though services NYC.
Marble Manufacturer Fabricator Distributor Importer Restoration Specialist Installer Stone Drafting Stamford Fairfield Westchester County & NYC
Vladimir Obrevko Stoneworks, also in Fairfield, is a custom fabricator/artist, though I cannot remember exactly who gave me his name. From what I gather from The Franklin Report, he has an excellent reputation and is a specialist, yet has an affordable rating, so if he does not perform the work you are considering, he might know someone who can do it.