One of the ways that you purposed aboved have to do with chaching plugin.
I have to tell you that none of the famous caching plugins work well with your theme. The thing is that the cart widger is cached too so the product number in cart is not updated when you add or remove products. I started this topic http://www.8theme.com/topic/w3-total-cache-cart-problem/
One of your staff members told me that you dont support 3rd party plugins!!This doesnt have to do with a 3rd party plugin, but you should have a way how to make it work with your theme.
So how exactly are you asking us to use caching plugin if it doesnt work properly?