Plus, having a bonus feat, humans are versitile enough to allow a player to use the feat to "customize the race".
Do you mean something like this?
New FeatStout [Background]Benefit: You gain +2 Con and -2 Cha. Your skill point at first level are reduced by four, and reduced by one at each additional level. In addition, you gain the stonecunning ability, etc.
Special: This feat may only be taken at first level.
New TraitStoutBenefit: You gain +2 Con, darkvision, the stonecunning ability, etc.
Drawback: You take a -2 penalty to Cha. You gain only one feat at first level (this does not include any feats you may receive as class features). Your skill point at first level are reduced by four, and reduced by one at each additional level.
Roleplaying Ideas: Characters with this trait might have a beard.