How to get the the user to provide domain registrant details before adding to cart?

[namhost]

We sell a domain type that has two different sets of pricing. If you register it as a local, you get a much cheaper price than if you register it as a non-local resident. 

I was able to get the two sets of pricing to work with "Client Groups", but the requirements are a bit tricky because we have resellers that also register domains on behalf of clients which can't be assigned to a client group. So that route won't work. Instead we need a way to:

1. specify on a DOMAIN LEVEL, whether or not that domain has "local" or "foreign" pricing, and a way to
2. Require the user to provide this and other registrant details as they add the domain to cart.

Is there any module or code anyone can direct me to?