So it looks like petites are disappearing and reappearing on the Canadian Anthro site. Though the petite link is still there, several petite items no longer list that petite sizes are available once you click on the petite tab! I have sent Anthropologie an email about this and will update you once I hear back.
UPDATE: Here's the note from Anthroplogie/fiftyone.com (their international delivery service):
Please be advised that not all items that we may offer in a petite size are going to available for international shipment. I apologize for any inconvenience this may cause.
Then why bother listing an item as being available in petites??? Totally WTF to me.