To alter the product pricing, you could make a series of product-specific discounts for each product, which affect the per-unit price of the product. By leaving the Discount Code blank, each discount would apply automatically when a buyer's cart order meets the Min. Item Quantity threshold for that product. Each next-higher qty. threshold would override discounts with a lower threshold, rather than compounding discounts together.
You can set a per-item flat rate on shipping; the best way to go about that depends on whether you want this flat rate to be the same for all products, or different rates for different products. If you want the first item to charge a bit more, you could use the Handling setting to add a surcharge for the first item that only gets added to each order once. As another alternative, you could simply configure your products with an accurate shipping weight and use our built-in USPS or UPS Ground rate-lookup feature. This help page explains more about our shipping calculation settings:
http://www.e-junkie.com/ej/help.shipping.htm
