I'm back from the convention and I still haven't seen or handled an 18" Siru.
Matter of fact, HI hadn't made an 18" that I can remember about 3 years ago. Uncle Bill ordered a Hanuman (dui chirra) blade on a WW2 handle. A half dozen or so turned up with a WW2 blade and the Hanuman handle. A few of us got then and said "Hey, this is just like a WW2, but longer blade. Make us up some 18" WW2's and next thing you know we have 18" WW2's, 18" AK's, 18" Sirupati's.
Also, about that time HI had 15" and 20" length. LeRoy Thompson had written an article a year or two earlier, and listed 12". 15", and 20". I asked Uncle, and he said they didn't have any left, and there wasn't a call for enough to do a run... apparently we got 6 people interested. So I am apparently the Patron Saintor Godfather of the reborn 12"ers.
Take that duckipuss!