While it isn't a Proto here is something you might find interesting, a 1990 or maybe 1991 Boarala cyclocross built with MAX Off Road tubing.
It looks a lot different now I was still noodling with bar/stem setup and cable routing.
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk