Get a full Lion install disc for a new MacBook Air or Pro

You'd need to download the image from Apple Store using the following:

Boot the hardware you need an image for from the Recovery HD by holding Command-R at power on time.

Plug in a JHFS+ formatted external disk.

Select the Re-install OS X Lion option and target the external disk.

Once the Installer finishes downloading, simply shutdown and unplug the disk.

Then, when you mount that external disk you will find a directory named Mac OS X Install Data on the root. Inside of this folder is the elusive, hardware-specific, InstallerESD.dmg image that you can feed to SIU or any other imaging tool of choice. Having this installer will now allow you to build out re-deployment images for all of your hardware until rollup installers are available