[quote=Silver Carrot]
I like the idea of naming them after colours.Another idea is naming them after the most common peasant jobs in that region, like Fisher, Weaver or Tanner
[/quote]

The problem with that is that ACTUAL peasants would have those names. Distinguishing a bastard should be giving them a distinguishable last name from the rest of society to bring shame on the eternal sin that siring a child out of wedlock/adultery is... or something.