In the 70's and 80's the old now bancrupt Harrington and Richardson made some 30-30 Toppers that had a tapered barrel. The barrel was about the same size at the chamber as present day handi's but was tapered from there down to the muzzle. I like to call it a slimline profile.
I own two such barrels and they do become available from time to time on the classifieds in this subsection of forums. Those barrels will not fit on the present day handi SB2 frame. I have also seen a nickel plated offering from that time period also. I wish I would have purchased it. Here is a pic of the "Topper" type barrel.