Moron, me.
After a 15-hour work day I got back to Epic #2 just before dark. Tried turning the engine by hand - atomarc's suggestion - and drew a deep sigh of relief when it turned, plugs in, by tensioning the belt and pulling on the fan. Hooked up my certified number one finest kind 12V battery, one of two in this little unit,
[IMG]http://thumb11.webshots.net/t/63/463/5/34/34/2467534340096215731LCZagQ_th.jpg[/IMG] and goshdarnit if she didn't stoke right up!
So I don't actually have any problem at all except maybe a bad cable and a severe dearth of meckanical skill, say, of the kind which might have made me wonder if a 12V battery with a dead cell, which had been sitting in my garage for over a year and had not been charged, but showeed 11V on my multimeter, might in fact not have had as much oomph on tap as my truck's 6V battery..
Go, now. Hide face.
Right after reconnecting the return spring on the starter pedal so the motor doesn't stay engaged and make rude noises at me.