Okay, here's everything I can find on shields and spiked shields.
[sblock=Item descriptions]
Shield, Light; Wooden or Steel
Shield Bash Attacks: You can bash an opponent with a light shield. See “shield, light” on Table: Weapons for the damage dealt by a shield bash. Used this way, a light shield is a martial bludgeoning weapon. For the purpose of penalties on attack rolls, treat a light shield as a light weapon. If you use your shield as a weapon, you lose its Armor Class bonus until your next turn. An enhancement bonus on a shield does not improve the effectiveness of a shield bash made with it, but the shield can be made into a magic weapon in its own right.
Spiked Shield, Heavy or Light
Shield Bash Attacks
You can bash an opponent with a shield, using it as an off-hand weapon. Used this way, a shield is a martial bludgeoning weapon.
For the purpose of penalties on attack rolls, treat a heavy shield as a one-handed weapon and treat a light shield as a light weapon.
Shield Spikes
Benefit: These spikes turn a shield into a martial piercing weapon and increase the damage dealt by a shield bash as if the shield were designed for a creature one size category larger than you (see “spiked shields” on Table: Weapons). You can't put spikes on a buckler or a tower shield. Otherwise, attacking with a spiked shield is like making a shield bash attack.
An enhancement bonus on a spiked shield does not improve the effectiveness of a shield bash made with it, but a spiked shield can be made into a magic weapon in its own right. [/sblock]
[sblock=Feat/Enchantment]
Shield Master (Combat)
Benefit: You do not suffer any penalties on attack rolls made with a shield while you are wielding another weapon. Add your shield’s enhancement bonus to attack and damage rolls made with the shield as if it were a weapon enhancement bonus.
Bashing
Description A shield with this special ability is designed to perform a shield bash. A bashing shield deals damage as if it were a weapon of two size categories larger (a Medium light shield thus deals 1d6 points of damage and a Medium heavy shield deals 1d8 points of damage). The shield acts as a +1 weapon when used to bash.
Only light and heavy shields can have this ability.[/sblock]
I'm a little troubled by the "Spiked Shield" entry, given that it claims 'off-hand only.' But at the same time it says a spiked shield is a bludgeoning weapon. I'm tempted to just call it wrong and move on.
Rereading carefully, I'm thinking your original interpretation is correct. "A spiked shield
can be made into a magic weapon in its own right," BUT "A bashing shield deals damage
as if it were a weapon of two size categories larger." So a spiked shield is still a shield, and it does not need to qualify as a weapon in order for Bashing to affect it.
By the way, meet
Spike.
I don't know if I'm going to dual-shield, but she's definitely going to be shield-centric. I'll decide in a few levels. I also figured that Wis shouldn't be a full-on dumpstat.
EDIT: I know you're "anything but humans," but my problem is that my characters keep ending up as elves.