On a Laptop with 4G RAM and Dual T7250 CPU install time for Clean install of Rc x-64 build 7100 took just over 15 Mins when booted up from a USB stick .
OK I have to install applications and find one or two drivers etc (you always have to do that anyway) but the "Base" install really didn't take long at all.
Maybe a USB should be an "Optional" install medium.
Was a great trick to run the "BOOTSECT" command from the "Install" DVD to get the bootsector on to the USB disk.
Now I've got a nice fast portable method of installing from a USB stick.
Now to see if it works on a Netbook with no internal DVD drive.
-- It does -- but beware there's no Prompt on the boot so if you re-boot during the setup it will start again from scartch so remove the USB stick after the first boot and insert it again quickly before the setup continues. I.E insert the USB stick again at the boot splash screen.