Well, I'm pretty certain something like this would work, but it would take some ingenuity (and wheel clearance) to get it strong enough and to make it fit. It's the only way I would personally feel comfortable doing it.
Basically it's just a framework that would be attached to the steering control rods so the framework would turn with the wheel. Well, at least it gave me the idea of plexiglass or lexan wheel skirts while I drew it up...
Wow... you just sent my brain in about 200 different directions with this. this could really work. This would also work as a way to make the rear wheel skirts even more simple.
The actual structure could probably be torch/solder welded if you used copper tubing or electrical conduit.
But, yeah, getting it welded to the A-arm (or whatever) would need something more solid. You'd probably want a fairly complex framework using 1/2" to 3/4" tubing. My "brainstorm" drawing is with 1.5" - accidentally punched in .75" radius instead of diameter.
Did some checking for pipe and tools - it would be pretty cheap to do. 3/8" pipe would be just fine. A 3/8" or less pipe bender is only $15 in my area, a cutter is $10.
Aluminum tubing would probably be the absolute best - weighs less than a pound for a 12 ft length of 3/8", .050 wall thickness. I think you would only need 8 ft per skirt frame. Not sure about the price of it - $3 a ft maybe?
There could be cheaper materials with thinner sidewalls that may work better.
Question : Why not *extend* the cover beyond the diameter of the rim? Since the wheelwell must accomodate the wheel, it should accomodate a larger wheel cover. For the point of argument, let's say a cover that exposes between 1 and 2 inches of the side of the wheel only. Here is a before/after example of what I mean :
Problems : Hard to get your hands on these unless you have a taxi driver friend. System may not attach to small rim of Honda Insight. A flat tire would almost invariably SHATTER the (better be plastic!) cover because the current design is "defended" by the real tire rim. Maybe this is an excuse to go with 18" rims (heh heh heh, just kidding, the tires for those things go flat driving over ice cream).
This may be a no-show solution, because I still don't know IF the turbulence between the wheel and the ever-so-close wheel cover will be a big negative factor.
This does not give you the perfect cover that you want, but I think it is a safer compromise.
If it was a rear wheel drive car you could make a wheel cover disc with a threaded nut on the inside centre and wind it onto the end of the stub axle.
The hub cap would be able to be within a coupl eof MM of the rim at all times no matter what th esuspension or tyre is doing.
Plus its mega cheap to do.
Of course with most front drive cars its impossible as the stub axle rotates with drive.