Yes I'm 100% sure.
I just discovered Rammus's defensive ball curl uses AP as well as armor. I bet it's a bug but I'm not going to report it. I've been experimenting with AP Rammus and holy cow... a Rammus with just 270 AP can kill a tower with his ultimate in 5 seconds. I'm not joking, try it yourself. Works on the inhibitor and nexus turrets too. 5 - 7 seconds.
Proof that DBC uses AP:
DBC level 1 damage to a purple caster minion (35 damage):
http://img808.imageshack.us/f/36343095.jpg/DBC level 1 damage + 2 rods to a purple caster minion (63 damage):
http://img340.imageshack.us/f/10602608.jpg/At DBC level 5 it does nearly 200 damage to a PCM. Considering without any AP, DBC only does about 70 damage to the PCM, it's a HUGE amount. Now, consider what this means...
This means that an AP Rammus who taunts a normally really crappy autoattack character like Soraka will do an additional 200+ damage to her compared to next to nothing for non-AP. On the other hand, it will do an INSANE amount of damage to a really good autoattack character while still preserving good armor and MR from DBC itself alone. Now, you couple this with his redonkulous damage from the ultimate with AP (5 seconds towerkill) and you're starting to see what I'm talking about aren't you?
The best part is. His q, the roll, is 1:1 AP. Yup. He technically has three AOE nukes. If AP Rammus with 270 AP (and that's a low amount of AP) rolls into a group of enemies, they will take nearly 700 damage just from that. Of course, you don't really want to initiate teamfights as AP Rammus, so feel free to roll in after the fight starts. Also, it makes it so freaking easy for him to clear minion waves finally. Anyone who's played Rammus knows his biggest weakness is his horrible, terrible ability to clear minion waves. Seriously, he's one of the worst. With AP Rammus, just one roll or one DBC and poof, all dead. Not even Anivia kills that fast.
You know what else, getting Rylai will give a slow to EVERY. SINGLE. ONE. of your AOE skills. Seriously. They won't be able to escape anything you do. Even the return damage from DBC slows them.