Custom shipping module or can existing one do this?

My client wants to use Canada Post for shipping, but wants to limit the customer to specific pre-defined choices.

He want to charge a specific shipping amount per item, which varies according to the product category. The amount also varies per shipping zone (N. America, S. America, Eurasia, and Australia/New Zealand) for some larger items, while other smaller items cost the same to ship anywhere in the world. He also wants the shipping cost included in the Paypal amount which the customer transfers to him, and he will deal with actually paying for the shipping himself directly.

He also wants to limit the customer to choosing Canada Post's Xpresspost for the larger items, as it gives more control over how the item is handled during shipping. The existing Canada Post module doesn't seem to allow any sort of control over what CP options are available.

This sounds like a custom shipping module to me, which I've been trying to convince him of, but if there's an existing module out there which could handle this, or even if there would be something close which might not need too much modification, that would be great to hear!

Thanks for any input/insight you may be able to provide.

Gary Hanrahan