The Mustang II hardware might be of some interest. All the stuff is readily available, nice (Wilwood) brake set-ups, all off the shelf. Some of the parts are a little expensive, depending on who makes and sells, one of the more interesting sites I've come across (from a cost perspective) for this hardware is Speedway Motors:
http://www.speedwaymotors.com/default.asp
Click on theit Street Rod products, then down to Chassis and Mustang II suspension and (tubular) controll arms. I know using 'merican products on the old Bug might rub some folks the wrong way - but you can't beat the availability of mass produced parts. This suspension design (and supporting parts) doesn't appear to be going away anytime soon. All you'd need is a custom subframe (like the one you're developing) that accepts the bolt-on tubular MII arms, spindles, brakes, R&P, etc. Having the subframe available allows the user to pick and choose from various manufacturers for the other items. Their complete tubular kit, including rack and (vented) brakes is $1400. Just need the appropriate subframe to attach it to! You have to admit, that would make a nice tidy package. Only drawback I can see is the available bolt patterns - but lots of alternate (non German) rims available. Wilwood might even have a blank hub and rotor combo that could be set up for 5 x 130mm. Might have to call it "German Resto-Mod Look".
Don't get me wrong, one-off is cool and can be beautifully done, but unless you go into production for all the custom items, if one ever needs to replace anything they'd have to start from scratch. I'm doing the same on a rear suspension, all mostly custom. I wish there were off the shelf parts I could use, but the stuff isn't out there. Just thinking out loud - you're custom suspension looks great Jason, definitely looking forward to hearing how it works on the road!
Jeff