Thanks a lot, Krisztian!!
I found the zenbook UX51vz , that is the big brother of the one you listed, and has ALL I need
8gb RAM, nvidia Gt 650M 2 gb RAM dedicated, i7 quadcore, 15,6' HD panel ( there is also a touch version) , good battery life, two 128gb ssd
Very light, less than two kilos!
It's a bit pricey, but still lower than the Mac.. ( 1500 euro more or less)
I've only to find where to see/buy it.. The asus site has not a direct online shop.
Thanks again
Gabriella