I would think the Beretta guns that preceeded the BL series would fit the bill. Most of the Silver Snipes had 26" barrels, and some came with a little stub rib at the monoblock and a ramp for the bead that was lighter than a full rib.
There was just a write up on the early Beretta production guns in The Double Gun Journal, and it was noted that if the 'snipes had a fault, it was that they were too light. I own a 12 with 26" tubes that can't be but 6 1/2 lbs, although it does have a ventilated rib.
I've always felt the same way about the 20 gauge ASELs, also. Just too light.
Best,
Ted
