Start price and consecutive price

I'm setting up an OpenCart shop for a client who is a printer, and I'm trying to get my head around how to get their pricing model to work with OpenCart.

What they want to do is have a starting price for a product, in this case a Brochure, of say $100. Consecutive Bruchures should only be say $1 each. So the prices should look something like this:

1 brochure: $100
2 brochures: $102
10 brochure: $110
100 brochures: $200

How would I go about getting this to work? I've tried mucking about with discounts and options but it's not quite gonna do it I don't think. Is there a suitable extension or is it something I'd have to custom build?

Should that be following since the first brochure is already paid for.
1 brochure: $100
2 brochures: $102 ($101)
10 brochure: $110 ($109)
100 brochures: $200 ($199)

I believe its at product level, You might be better off looking at a custom module to allow flexibility.

The price should actually be calculated like this in an ultimate scenario:

X + (Y * Z)

X = Start cost
Y = Quantity
Z = Cost per item

So if you want to print 100 brochures at a start cost of $100 and a per item cost of $1...:

$100 + (100 * $1) = $200

So, basically, all that's really needed is an option of adding a fixed sum to an order of a particular item, which is static no matter how many copies of that item you purchase. I would have thought a module for this should have already been built for other similar scenarios, but I can't find anything so thought perhaps someone would be able to point me to one? If not I guess I'll just have to commission someone to build it for me...