So, I wandered around Home Depot after work, and found nothing. That's just as well, because I couldn't get help either. After that, I stopped at a sign shop in town, and they gave me two election signs and an odd, long scrap for free!
The election signs may turn into a partial front under-tray.
Within the past hour, I built a partial grille block. I've got a trip to the Rochester area (over 200 miles round-trip) coming up this weekend, so if it has an effect, I'll definitely notice then. I don't think I can crack 32-33mpg on the highway, even if I keep it to 65. Of course, I don't have cruise control, which is irritating, but I do my best to be steady.
Before:
Parts:
After:
It's not easy to see, but I did fill in the little fake brake-cooling ducts, with the small rectangular pieces in the 2nd picture-- I am too lazy to cut them to fit. Maybe some day, I'll get some expanding foam and bondo, and smooth those over. I've also got enough material to do an upper block for winter!