Here's my situation. My big bad dragon had kidnapped one of the PCs are robbed her. That meant he'd gained an unusual variety of magical gear that I wanted to use against the party. Maniacal laugh and such, sure, there’s no listing for dragons on the Magic Item Slots for Animals chart.
Over the course of my research I encountered the wildshaping rules. Rangers discussed their animal companions. Paladins had questions about their mounts. The 3.5 version of the Draconomicon came up, and the always tricky question of in-game justification reared its horned head: “Such external dependencies are mortal crutches unbecoming of a true dragon!”
In the end I simply let my dragon wear its captured booty and nobody called me on it. I'm curious to hear how you guys would handle it though. What magic items do you allow your critters to wears? Do you fudge the rules in corner cases, or are you comfortable making a few judgement calls when it comes to weird body types and gear?