Apply and make visible coupons just like 'Volume discount'

[lab_n_chemicals]

Volume discount, new subtotal show up in the Shopping bar as soon as a qualifying product is added to cart. These are line item volume discounts. One of my vendors' discount structure depends on total dollar value of ANY combination of their products. These products (over 3,500) are grouped within separate catagories - common theme is manufacturer. Coupons do this nicely if I were to pick the items one by one. But traditionally (1) coupons depend on customers knowing about them and (2) coupons show up at the end of the order. But a hidden coupon doesn't get me any "add to cart" action.

How can I get the coupon feature to display and apply just like the Volume discount feature?
i.e.
Show available coupon for the product if there is one?
Apply coupon to item(s) in basket just like volume discount?
Also show coupon value and new subtotal in "Your basket" in sidebar?

Anybody in dev able to shed some light / solution?

Thank you.

[lab_n_chemicals]

I guess from the lack of response, its either too silly or impossible.

Basically, i need a volume discount per manufacturer (across categories).

Any ideas?

Developers: Please respond since this is a best selling line for us.

Thank you in advance.