So if you missed the amazon deal, here is a very similar, and slightly cheaper deal at Rockler. This kit has riser blocks, as opposed to clamp extensions.
From the site:
Sturdy jaw construction with metal-reinforced plastic housing
End clip is easily removable without tools so you can convert the clamp to a spreader
Adjustable, removable plastic risers lift your work off of the bar to eliminate marring and glue smearing
No-mar clamp faces are glue- and solvent-resistant
Clamp faces are removable to fit optional accessories like the Pivoting Jaw Faces (#51431, sold separately)
Included KP Blocks let you set up a stable frame clamping fixture, ensuring square corners and no-tip performance