Hi Jack,
Yes, the alloy blade holder is really strange, and it is amazing to me that it has survived the test of time so well, given that the blades are so long in proportion to the disk. Even the Southern Cross KX-C only had part alloy and part steel frames for the wheels (and they were a separate feature, not a part of the base). Incidentally, the KX-C also had alloy connections (midway joins so the bars could be folded down) on the otherwise steel handlebars.
I'm guessing whatever this mower was, there are only a few of them still in existence.
