TSM: Just in case you haven't tripped in awhile and to simplify what you have to go looking for. Dwarf gets a -4 for size and doesn't get it's stability bonus because the barrel wouldn't constitute stable ground.
Okay, been wracking my brain over this one. I don't think I've ever tripped anyone (I rarely play melee fighters, and the DM I normally play with has a low opinion of trip) so bear with me for a moment. I'd like to be sure for when you try to pull this crap on me
I got the dwarf doesn't get his stability bonus (poor bastard), but why does he get a -4?