Okay.... I'll accept that you haven't had any other agenda than to find out whether people are measuring their CdA.
I haven't needed to in the past as most of my designs have been for un-faired recumbents. But recent interest in my leaning trikes, especially WRT to fairings and my own weather related needs where I now reside have me working on a fairing design. While initially this may be executed in Coroplast without compound curved surfaces, at some point I'll be looking at vacuum formed polyethylene sheets.
At that point, I will probably get into one of those on-line CFD services to fine-tune the 3D model, then run tuft tests on the final shape out of the mold. The thing is that I wouldn't be looking to tweak the design as I plan for it to be relatively optimised and compromised for both aerodynamics and commuter functionality. So would I need to measure CdA on a regular basis? Probably not, since I'd already be looking at the minimal sectional area while still being functional as a daily velomobile, while the shape itself will be as laminar as I can get it within those same dual constraints. I could imagine testing to see if accessory features were impacting drag, but the only external I can think of at this point would be mirrors. Everything else, including lights would be part of the overall surface and not impact the drag.
Now, seeing as how you are from a sport in which 6 seconds can cover the top three spots, it seems to me that the power sources in your game are relatively well matched, something that hasn't happened yet in recumbent racing. For the moment let's assume that since you've been on a number of cycling forums, that this would in fact be the typical UCI-type 1-hour time trial. Unlike recumbent racing, the vehicle form is highly restricted there, so in fact, CdA is very, very important to the designer, especially since rider power at the elite level is going to be the same within say +/- 2%. The smallest details can play large when both input power and overall shape are nearly uniform across the field....witness the new sequential shifters from Zipp in which the levers return to a center (and level) position after a shift.
As I said this kind of uniformity does not apply to recumbent racing... at least not yet. Measuring CdA before and after a change is going to be rare on vehicles where tweaks are almost all internal and external changes are considered to be a core re-design of the entire vehicle.
So no, I don't expect to measuring CdA anytime soon. If I did, I'd probably not bother with a power meter as that same expense can be put towards either wind tunnel rental or the building a small backyard tunnel both of which will provide consistent and accurate results that can also be viewed with smoke, tufts or other aids.
I hope this clarifies things. Finally, please understand that the tone of your posts so far has seemed to show a general disappointment over the non-high-tech-ness of recumbent design methods, and that may often be interpreted as disapproval. My apologies if I interpreted your contributions in that way.
:)ensen.