Tier pricing for product variants, and bulk buy discounts / displaying price

We are setting up a wine store. Most wine comes in a standard bottle size (75cl) but you can also get half bottles and magnums for many of the wines we will be selling. We can use product variants to handle this, but since most people will want to see the standard 75cl bottle price, we only want to show the 75cl price on the products grid page, rather than "from £[price of cheapest variant]".

Additionally, we want to offer discounts for buying a case (12 bottles) or half case (6 bottles). Again, in the product listing page, we just want so show the single bottle price, possibly with some text that says "discounts available for case / half case".
We are using the Traction Theme and Ajax Filters.
Is there a way to achieve this with standard nop, or do I need to make some customizations to the nopCommerce code, or is this not possible due to the fact that the data is returned by Ajax Filters?
Note I have posted a similar question on the nopCommerce forums (http://www.nopcommerce.com/boards/t/36045/tier-pricing-for-product-variants-and-bulk-buy-discounts-displaying-price.aspx) but as yet I have not had a response.

Thanks in advance.

Hi winebear,

About the first question - you can create a product attribute, for example Bottle size, and create 2 values for it: Half bottle with price adjustment -5$ and Magnums with price adjustment +10$. In this way, only on product page the customers will be able to choose what type they want to buy. An addition to this, you can enable catalogsettings.dynamicpriceupdateajax and catalogsettings.enabledynamicpriceupdate settings to that the price will be updated when the customers choose the type of bottle they want.

About the second question - one of possible way to show custom text over the product will be use the Product Ribbons plugin. 
For the discounts of the products when buying a 12 bottles or 6 bottles, you can use the Tier pricing. Simply, create 2 records, for example:

Quantity 6 with Price 20 and Quantity 12 with Price 18.

Another possible solution for this is to change the PriceCalculation service, so that the prices in the nopCommerce will be calculated by your logic.

Hope this helps!