You are correct, Sirs! I have a 110/74 BCD crankset on one of my bikes. It is a triple, but I am using it as a double for the time being and even have a 34T small ring I can put on for extreme situations. I have the appropriate bb for the triple, I just haven't felt like putting it on. But John E is right, 38 is as small as you can go on 130 BCD cranksets.

Niall, the short story is, avoid going to the triple if you can because it can run into money. See if you can accomplish the same thing with larger gears in back. My favorite 9-speed cassette is 14-25. I can't even drive 52/14, much less anything higher.
Regards,
Raymond