Check out Geoff's video... With the Shaper you could probably make some sort of form (even out of 20mm MDF, and use maybe a 6mm sheet to provide a large flat top surface without any bumpers and using maybe shellac/CA (not gluten free) to seal all the "non-sucking" surfaces/perimeters.

Probably many options available...that's why often I just bite the bullet and buy whats on offer rather than reinvent zer0-G.

PS.
I should probably paint that foot pedal pink... I've had my pink beatle boots since 1980, and no spider has ever nested in them. 

If your first cut is too short... Take the second cut from the longer end... LBD