Hi Goncalo, I haven't looked at the links you posted, but have you considered a ceramic knife?
I bought one about a year ago, and if you are careful with it, it will you serve up you well. Not an all round knife for sure, but ultra sharp. Very good for non hard vegetables (I wouldn't use it for carrots). Onions fine. Having said that though, you have to be very very careful not to chip its brittle blade. Never needs sharpening... If you tried to though it would smash.