Hi--Thanks for the interest--I don't have a metric ruler here, but I got this email from a Mr Kaz Yoshida at Sugino:
>Mr. Drew hello.
>If it is 113mm that the BB length, the chain lin becomes about 43mm when the GS crank is used by the >track racing.
>It is possible to use it also with the thing of which manufacturer in case of being interchangeable BB >SHIMANO it.
>Please examine it.
>SUGINO CYCLE INDUSTRIES,LTD.
The crank is a Suginio GS (looks like 65 too..), and YES, it does look like a double, but it has 144 mm bcd, and a very low Q factor. I just figured that it was a track crank where I could put the ring on the inside or the outside. And ANYWAY, the part that is about to hit the chainstays is the back of the chainring bolt, not the spider itself, or the lip where an inner chainring would be anchored. I have about 1.5mm clearance there, untightened.
The hub is a rough 42 or 43 from the quick measurement before I bought it (promax NJS), and I'm assuming that I got the right quote from Suginio. Maybe this frame has intolerant chainstays?