Like the OP, I am also traveling between Shanghai and Hong Kong. As a matter of fact, I will be traveling the opposite direction. From Hong Kong to Shanghai around 6/8, 6/9 - one of those days.

The cheapest tickets I can find are around 1400 HKD w/o tax and tip. Is there any cheaper?

Also, another problem is that the domestic luggage limit is only 20-25 Kg for all bags combined, is there any way around this? I'd prefer not to be hit by a huge fine!

Thanks,
Mitchell