I would imagine that Threadcromancy isn't permitted by the moderators...
Actually, despite any impression to the contrary resultant from a minority of members, "Threadcromancy" is not only permitted, but wholeheartedly endorsed by the staff here - as you've noticed, there's some excellent information no less interesting simply because it's been neglected for a while. Nevertheless, starting a new thread relevant to your interests is of course a great way to offer your insight & gain more information... *shrug* It's up to ya'll ofc
I'm personally fascinated by velomobiles/velocars & tadpole trikes in general, though there are some difficulties with the general concept. Expense is however not necessarily one of them, provided ofc you've some fabrication ability as there's a plenitude of DIY plans. A great resource for low cost, practical plans is
Atomic Zombie Extreme Machines! - Bikes Trikes and Chopper Plans - one of my favorites being the 'Warrior Tadpole Trike'
Warrior Tadpole Trike - AtomicZombie.com - YouTube member build example:
http://motorbicycling.com/f44/amped-up-warrior-27931.html
Where it gets ...tricky is ofc the body shell fabrication, wheelbase width & legality. It's extremely unlikely a body could be found that's ideal for a custom build and even if it were - just about all specialized velomobile & recumbent components are insanely overpriced. While just about everything other than the body shell can be found through other, more affordable sources or simply made - the body is a stumbling point, though not an insurmountable one if you've the time & resources.
While (pedal) trikes in any configuration are road legal everywhere that I'm aware of (motorized is ofc dependent on local law), width becomes an interesting difficulty in regions that lack sufficient roadside/shoulder room, this would be even more of a problem with a passenger velocar with a side by side seating, if passengers are allowed at all in an unregistered, uninsured vehicle (which, admittedly I've not looked into).
What is particularly unfortunate for velocar construction here in the states (as far as I know) is most, if not all jurisdictions outright forbid the use of any four-wheeled pedal vehicles, even if not motorized - as soon as you have that "extra" wheel it's considered a "home built automobile" and subject to all current inspection standards and requirements as such, which while also not insurmountable, radically changes the parameters of construction, resulting in something that's likely quite different from the vintage style velocars pictured.
Nevertheless you're completely correct & I'd like to thank you for digging up these excellent examples, you're "getting my wheels turning" so to speak lol - There is such a huge amount of potential in this almost forgotten concept and what with rising gas prices I hope to see a resurgence of these "low tech transport alternatives" people devised during the rigors and shortages of wartime. As you've probably noticed, I'm building a motorized tadpole not completely dissimilar from some of what's pictured (tho recumbent for comfort & efficiency), but for now at least I'm forgoing a body shell... maybe next year though, who knows? Some of these pics are quite inspiring