The biggest "problem" I find to shipping overseas from Canada is price and lack of tracking number. It seems like Canada Post wants outrageous amounts to ship overseas and then states that they can only guarantee tracking until it leaves Canada. There are no guarantees for delivery times to certain countries and this is what usually kills deals for overseas..
This seems to reflect most postal offices though, I know an A600 I ordered from the UK, the sender said that royal post wanted more than 70 Pounds to ship it without a Power supply, just the A600.
I just had an inquiry in my A500 Power PC card to Rome, Italy and Canada Post wanted $70 or $150 (expedited) also.
I have no issues what so ever with shipping as long as the buyer is paying, but I do have an issue when the buyer whats me to check out ALL the alternatives (like fed ex etc), and then to spend all that time to hunt down a cheap alternative for a $15 part just to find out they are not interested because of the shipping costs. I am not making any money on my website, nor do I have a car to keep running back to the post office for more quotes, nor do I have a business shipping account with anyone, so I just tell my customers that I prefer to ship within North America to keep the hassle factor to a minimum.