David - there's not word on the street because there are none on the street yet!~ It's a bummer but we are having a tough time getting them manufactured at the shop we are working with - that's why the availability is March.
AS far as the weight - they should be equal in weight to most other concaves. We've got taller kick & concaves (plus the slider bottom), but the deck is really dished out and we take weight out with the thumb rails & end grooves. Our prototypes were awesome - you can really feel the extra control and the dished out deck makes it feel like you are riding "in" the board, if that makes sense.
When they do come out they will be sweet.