Attacks of Opportunity while holding a bow?

[the Jester]

The best way to do this that I've seen is to have more than one set of arms (girallon's blessing from Savage Species does the trick, but my campaign's had a very similar spell since the heyday of 2e).

If your melee weapon isn't in hand, you can't make an AoO with it. Again, I have a custom feat workaround (called Hidden Threat) that, with Quickdraw, lets you make AoOs as if armed with your weapon as long as it's on you.

 

[3d6]

Same with the spiked buckler.

Shield Spikes: When added to your shield, these spikes turn it into a martial piercing weapon that increases the damage dealt by a shield bash as if the shield were designed for a creature one size category larger than you. 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 (see above).

Can't put spikes on a buckler.

 

[MerakSpielman]

Well that bites. You'd think a single, narrow spike in the center of a buckler would be easy enough to implement, and easier to wield than a spiked normal-sized shield.

 

[0-hr]

A spiked gauntlet may be an awful weapon, but it is more than enough to compeltely stymie that gargantuan dragon trying to grapple you.

(That's why, IMC, damage done by the grapple AoO only adds to your grapple check.)