OldGreyBeard said:
I think you can increase your chances of getting the Red Brotherhood map by choosing to be a bard. In those games I've chosen that, I've actually had several Red Brotherhood maps. The later ones don't give you a Qualis Gem, of course, but they're still fun.
Indeed, there's the hidden stat of "Rumor Interval" behind the character creation options, which the lower it is, the more likely you'll get a valuable rumor from NPC-s (e.g. Map for the Red Brotherhood Hideout, loot for the chests in Rane and Valonbray, unique spawns spawning in, troops to offer from ransom brokers, etc.). And the 'bard' apparently gives you one of the lowest values (=highest chance) for that.
To see how much rumor interval you'll get for each creation choice, check this page on the Wikia:
http://pop3.wikia.com/wiki/Character_Creation