Zencart extensive shipping module needed

I need a quite extensive shipping module for our new Zen Cart store. It would need to be the kind of thing that would have to be adapted for future stores as well. I would have maybe 400 items total on the website. Of which 350 items would follow the same rules being under $100 flat ship cost of $10 and over $100 10% of order value for shipping (if shipping to the lower 48 states). If shipping outside of the 48 states, or to other countries, then would need to take actual weight based on items ordered (and box sizes) and calculate using UPS engine. for the other 50 items it would need to take pricing based on weight of items, and box sizes, using the UPS engine for calculating. As stated, this module would need to be copied to other future sites and other groups of different products would need to be added to this logic as well with the possibility of changing the flat rate of $10 to $20 or 10% to 15% or who knows what other flat rate the owner decided upon! This needs to be easily configurable, easy to add items to in the future, easy to change and as simple as possible for even a non computer savoy person to use. This is a RUSH job!