What was used on that Panasonic road bike that they showed that weighed about 10 pounds total?

I dunno... If we're going to build vintage weight weenie bikes, shouldn't we make them functional, and able to support our own weight safely? A 16 pound hillclimber that you can ride, makes more sense to me than a 13 pounder that you need to drive to the scales.

I'd stick to 753 or Ishiwata .019 as my frame material then.

I believe you are referring to the Panasonic Ultralight track bicycle. The bicycle actually used mostly standard parts that were lightened by various metal removal methods. Rims were drilled with 3 extra holes between each of the 24 spoke holes. Hub webs were reduced and the bearings exposed. Hollow axles with half width nuts. Sugino crankset milled front and back and spider drilled through at the normal flute locations. Chainwheel thickness reduced and inner web removed. Lower webs of Mikashima pedals removed. Wall thickness of seat post reduced. Thickness of saddle base reduced and cutouts incorporated. Stem extension drilled and bottom of stem blocked to allow use of super short expander bolt. I have been unable to locate details on the frame tubing other than it was CrMo, double butted with extensive lug cutouts. I believe there was a later version that used a Dura Ace 10mm drivetrain to reduce the weight even further.

The wheels at the shop, I'm pretty sure, are early Weyless instead of Hi-E. Pretty light, although the owner wouldn't put a price on 'em. I can probably brow-beat 'em outta there, but I need to bring my scale down to see just how light they are. I've never seen a Maillard Course; I suppose they were all aluminum? and Record Seta Extras are very hard to come by...the lightest tires at my immediate fingertips are either CX's or very light panaracer TT's. (actually, I think I have just one tt, I carry it around as a spare. If I can find another then that would be a good weight weenie choice, and still sorta rideable...)

No way I would dare ride that.

All aluminum except for bearings, springs & a few other internal bits.

Here's one: Maillard alloy freewheel

This one weighs in at exactly 129 grams.

Here's an interesting crank for your project, a Topolino:

https://cgi.ebay.com/ws/eBayISAPI.dll...MEBI%3AIT&rd=1

you are exactly right! I have some topline mountain cranks - a pair on my hardtail, and a pair in reserve. They were some of the lightest cranks on the planet in the early '90's - I suppose that they might compare well with modern stuff. They had a smallish maintenance issue: they broke when you hammered on 'em sometimes (I never broke mine, tho). I'd forgotten that I even used 'em...I'll watch this pair.