Jobs was hinting through email that you must go SL -> Lion each time.
For a company that has a philosophy that strides on ease-of-use and simplicity, that is unnecessarily long-winded.
Your not really supposed to install it from disc, its meant to be installed from the MAS.
Shame there isn't an option to boot into the MAS, like the built in disgnostics. That way you could hook it up to the the internet, boot into the Mac App Store and install that way. Would mean you always install the latest release so no more having to install the combo updates once you're up and running
Edit : Thinking about it, you should be able to netboot and install
Indeed, is it in Lion that you can restart to Safari mode? Thereby booting to a secure browser (Safari) for things like web kiosks etc.
Glad there will be a way to just flat install Lion, my Windows mentality means I want everything clean with no trace of old OS install to ruin the experience...
You can burn Lion to disc and install fresh from it. Heres how-to