The OA shapechanger prestige (updated to 3.5 in dragon 318) not only grants 3 wild shapes per day at 1st level without requiring wild shape as a prerequisite, but it explicitly keys the wild shape HD limit off of your character level, rather than class level like the druid does. keep in mind that the duration still functions like the druid class feature, and is thus based on shapechanger level (plus qualifying stacking prestige classes).
the feat requirements (alertness and endurance) are a pain, but the concentration 10 is pretty easy to pick up. if you are focusing on wild shape and are multi classing picking up a single level is an easy way to make up for lost HD potential. wild shaping ranger kicks in at 5, this can't be taken until 7, or 6 with early entry. this is my preferred method for qualifying a psionic build for wild shape. as a single level dip, it is quite nice.