Chris,
Sorry for the delay. For whatever reason I wasn’t notified of your post here by ww.wp.xz.cn. The question you are asking is one that is specific to WooThemes, as the code base in question is theirs. Having used their system extensively I would advise based on your post that you review the features of their dynamic pricing plugin. It may be a PERFECT fit.
http://www.woothemes.com/products/dynamic-pricing/
I worked with wp-e-commerce and shopplugin and tried WooCommerce for my latest project. It is very developer friendly, almost bug-free and working with developers and translators via GitHub has been a breeze. Totally different to what I experienced with the other ecommerce plugins.
Totally agree jessor. WooCommerce is awesome, the support is fantastic. I’ve been in ecommerce for close to a decade, and have really come to admire the simplicity and flexibility that Mike and crew have created. Yes, there are situations where you may want something different, but honestly, for 99% of business, especially ones using wordpress, WooCommerce is top of the list by miles.