There are several pusher-prop monoplanes with little leading edge sweep, but they are typically more modern aircraft, for example the Piaggio 180 and the NAL Saras. I haven't seen any that have NO leading edge sweep at all, though. Even that UAV thing has a bit of sweep.

EDIT: Have a look at this thing.

you loock this manual for Weighing the Aircraft and Determining
the Empty Weight Center of Gravity.

WHEIGHT and BALANCE HANDBOOK.
http://www.faa.gov/library/manuals/a...-H-8083-1A.pdf

Thanks The Grunch!

That certainly helped to clarify the conventional configuration: The tailplanes have a downward lift to counter-act the CG being ahead of the Center of Lift:

http://en.wikipedia.org/wiki/Piaggio_P.180_Avanti

"The arrangement of the wing surfaces allows all three to provide lift, as opposed to a conventional configuration, where the horizontal stabilizer creates a downward force to counteract the nose-down moment generated by the center of gravity being forward of the center of lift."

The other aircraft you mentionned is still in trials or pre-production, so the Piaggo is most interesting...

Thanks to everyone who answered.

Gaston