Keep looking at the sites. Many sail brokers can add the sunbrella for you for nominal fee. The savings over a new sail are worth the cost of modification. I've just bought a great sail from Bacon's in Annapolis and know of several others that are happy with sails from Minney's. Many sail brokers will take a photo of the sail for you if you can't look at it in person. Most have a return policy. Prices are much more negotiable than you may think.
Keep looking and be prepared to buy when you see what you want. Fall/Winter is the best time to buy because they will be all picked over by spring and not much is added in summer.
Have you tried thesailwarehouse.com? The have a ton of C27 sails. Pay someone to add the black sunbrella.
Sabre 38 "Victoria"