The 16 inch wheel (lack of) efficiency thing: i don't know and didn't mean to imply it do or that they must be. But have heard such sentiments uttered and backed by reasonable people that were into 20 inch.
As for the other efficiency, that would be drivetrain/frame stifness which supposively is somewhat lesser on the Brompton. Again i don't know this for as fact, but to my mind it seems plausible.
What does seem to be agreed upon by quite some folks is that the smaller the wheel, the more comfort and long/fast descents can (not: are) become an issue. Also the fact is that there are way more (good) tire choices for 20 inch.
Thanks for those thumbnails! I must say it looks promising for the most part, i like the super low gravity design (similair to what i have now, probably even better). The der hanging crazy low to the ground would not do it for me but i would prob. run gub gears anyway. Nice bike!
@ Peter, interesting notion... i wonder why they put the project on hold. Many reasons could explain it though. But to me the Tikit does resemble (and thus validate) a Brompton or even certain Dahons almost as much as a resembles a BF.