Have you checked Pegasus racing for formula car units? Not so cheap though. There are also nice pieces available form 600racing and another outfit that does small circle track cars. You can also look at pictures of parts for dirt circle track cars, there is a variety of choices there for ideas. They are as you describe with t he addition of sheet metal gussets for the steering arm. Those types of places also sell the tapered steel inserts for ball joints and the axle stub to fabricate your own upright.
There are also some pictures on this site, you just have to read it all to find them!
Triumph Spitfire uprights are around 5 lbs., how light do you want to get and is this the place to find the last pound or two? I understand the Pinto and Miata units are too big...
I came across Pegasus in my googling; pricey and inefficient flat topology.
Thanks for the tip on 600racing; I emailed them for weights of these (reasonably priced) parts http://store.uslegendcars.com/site/depa ... 34A0874BC2
I have looked at various dirt track sites, but those uprights are mostly designed with kingpin bushings for live axles, and seem to be low very low height.
Another pet peeve I have is the use of solid axles, whose small diameter necessitates a heavy section to take the bending loads.
Also there's no reason to have any physical structure on the axle centerline; it just creates a longer load path from tire to wheel center and back out through the upright to the wishbones.
So why not a much larger, say 2" dia, hollow axle using thin section bearings?
Also why does no one seem to use the thickness of the upright to space the bearings farther apart?
Fair question about the weight.
I think a fabbed upright could be ~2 lb. Would 3 lb less out of ~40 lb unsprung weight be perceptible? Beats me.
What we really need is lighter tires with load capacities that aren't 2 - 3X more than necessary.