I need to agree with the other posters. A good crab cake should never be sauced. The reason for this is quite simple: the sauce is built into the crab cake.
Here is a baseline recipe for a Baltimore style crab cake:
1 egg (maybe 2)
1 or 2 spoons Helmunds
a little mustard
maybe a shake of cayenne pepper
a little black pepper
a little parsley
this is wisked together, and tossed with
1 lb MARYLAND CRAB MEAT, WITH FAT (emphasis added, and also yelling)
to this is added some cracker crumbs (a few saltines beat with a crab mallet), This makes about 6 cakes which are FRIED in a little butter, or maybe Crisco or vegetable oil. NO BROILING (yelling again).
Notice there is no Old Bay, which is for shrimp and tourists. And no bread.
So the mayonnaise, mustard, and especially the CRAB FAT make a sauce inside the crab cake, and the crab fat is tastier than anything else known to man. The source of the problem though, and the reason you are considering a sauce, is that restaurants do not serve this type of crab cake-- it is not commercially viable, and the fat is generally absent in commercial crab meat available today. I am not even going to mention the imported crab meat, other than to say that I am not mentioning it.
What does all of this add up to? Like everything else, if you want something done right, you need to do it yourself.