Anything other than FlatRate shipping?

We really need the ability to calculate shipping, not use flat-rate. I have used WPEC in the past and have had far too many problems with the plugin in general, which is why we've switched to MarketPress for all our new clients, but I'm worried that flat-rate is the only option. Please tell me it's not. And if it's not, where can I find the option to calculate shipping based on shipping address and weight?