The Nordleads are lightweight, from www.clavia.se
They are synthesizers (virtual analog) and don't play back samples. A second hand Nordlead or NL2 is affordable, but if you have the money go for the NL3.

I have two Nord Modulars and Clavia stuff sound nice. Since you don't like Roland, I get the feeling you're after something different. Remember, the Nordleads don't play samples of acoustic grands. String sounds, choirs and synth sounds are excellent though.

-tek