RFQ:OsCommerce Script Mod needed

This is a request for quotation: We are looking for someone to create the following mod for OsCommerce 2.2a We are looking for 3 tax systems (os commerce only allows for 1) Tax 1 Tax 2 Tax 3 The third tax MUST be based on volume (weight) and can not be percentage based. Example I sell a 23 Liter beer kit. Taxes on this kit are at .13 per liter the total at check out should read 23*.13 = 2.99 All three taxes should be able to be applied to all products, with an an Itemized list on check out (and invoiced). Example: Subtotal $xxx Tax 1 $xxx Tax 2 $xxx Tax 3 $xxx Total (all of the above) These fields should be applied when new products are entered into the system and the tax rates should be able to be adjusted in the admin section. If awarded, period will be within the next 2 months.