Agreed, some of the Paradigm models can be a bit bright, although my older Atoms (Version 2?) are pretty mellow and rolled off in the highs. Another monitor that might float your boat is the Silverline Audio Minuet ($600/pr list, street price somewhat lower). With a sub, these should make a nice full range system. They are not really rolled-off in the treble, but they are quite smooth, IMO, and have a little of Silverline's trademark dip in the "brightness" range (~4-8kHz). I've also read that the Aperion monitors, which use soft-dome tweeters are a bit on the warm side, but can't say this from hearing the current models (but older models did indeed sound a bit warmish).
Away from those, focus on non-metal tweeters (soft domes) and/or look for speakers that don't have a crossover above 2kHz or below 6kHz (which would be unusual in a multi-way design).
Away from those, focus on non-metal tweeters (soft domes) and/or look for speakers that don't have a crossover above 2kHz or below 6kHz (which would be unusual in a multi-way design).