OSCommerce Supplier Area & Multisite

I currently have an OSCommerce site that I need modifying. This is an old project that never got completed and is now overdue, Timeframe to completion is of the essence. There are two mods needed ( Part A is what is most urgent, part B can be completed later):- A) Supplier Area - This mod will require an admin area that suppliers can log into using a unique provided password and login name that will allow them to enter their own products, complete with images, prices, keywords etc. I need to be able to select certain product categories in admin that each supplier has access to. Within these categories the supplier can enter his own sub categories along with the products. There needs to be a unique identifier to only allow each supplier to only modify his own products. On the section where the supplier enters the price for each product, I need to have them input the price that they sell the product to myself, there then needs to be another box stating sale price that will be worked out automaticaly from a percentage mark up that I can set in the admin for each supplier. Like the affiliates contribution, each supplier needs to be able to see his sales figures for each month on his log in area. Also I need to be able to see a list of the sales figures for each supplier. On the order email I need a seperate order email to be sent to admin with the product code, description, the cost price the list price and supplier. B) Multisite mod - I need to have one admin using one database but to have multiple domains, each with their own designs, store name, store meta tags and sharing users. The products need to be selectable for each store on both an individual basis and by a select all in category. There needs to be an easy admin section for adding urls. Please remember that this is urgent and I'm expecting bids near to the $300 mark.