One source for colour matched paints I have found helpful is a finish supplier to the cabinet trade. The guys at the local shop are very helpful and wizards at matching finishes. They don't mind dealing in small quantities such as we use either. For my last project I used a two part polyurethane put out by Chemcraft International. This is available in various sheens and infinite colours. The catalyst can be very hard or softer as used for exterior applications. Prices were reasonable - less than hobby paints.