Traveling From Canada to the U.S.
I found this document (pdf) from CATSA which should help clarify what you can and can't take on board:
1) No carry-on but you can have one purse/small bag no bigger than 12 x 10 x 5.5 (think Side Effect, SCB, MCB, Packing Cube Shoulder Bag and Ristretto for Netbooks).
2) Items allowed must be carried in pockets--but they don't limit the number of pockets you can have. (Scottevest, Tilley Vest)
3) Except for the larger bag, and your extra clothes, there's not much else you can't take on that you couldn't take on before.
4) It's totally ridiculous. (Sorry, just my opinion.)