So let's keep digging...
To calculate the projected area of an AirTab, I took this picture on maximum zoom (and kept it in the center of the viewfinder to minimize lens/perspective distortion):
Traced its outline in Photoshop and made it into a 2 colour image:
Using the Image > Histogram... feature there are 9,480 black pixels in this image. The 61 pixel height of the black corresponds to 26 mm (1 inch) height of the actual AirTab. So 1 mm = 2.346 px; and 1 mm2 = 5.504 px.
So the projected area of the AirTab is 9480 px/5.504 px per mm2 = 1722.25 mm2, or 17.2 cm2 or 2.67 square inches.
Times 8 AirTabs (though Donee pointed out the outer 2 probably arent needed): 137.8 cm2 or 21.4 square inches!
Taken together, that's pretty much the projected area of a door mirror! OK, a small mirror.
Just eyeballing it, two delta-wing VG's set at the angle Mitsu used on the EVO are probably 1/3 the projected area of one (double vortex producing) AirTab.