as of right now i cannot find those concepts trucks of years ago, but i am still trying.
i did find a "sort of" new cabover truck that is still in the concept mode.
here is one concept:
Renault Radiance concept truck shown at Hannover IAA
and here is at least one other:
Volvo BeeVan Concept Design is Ahead of the Curve | Design News
i too remember those cab under trucks. i am glad they never came to be.
we have an advantage right now, and that is our height in the cab. we can see clearly for about 1 mile ahead. if we were to be "under" the trailer, we would be at the same view point of the 4 wheelers, and that ain't no advantage at all......we wouldn't be able to see trouble up ahead like we can now.