Ben, I was looking through that S10/Sonoma spec PDF that Slow_S10 linked to, and noticed a few possibilities to consider.
Our trucks are 1995s, but the body sizing is very close AFAIK to the 2001 the PDF details. The regular shortbox and the sportside are both about 76" long. Both boxes are 68" wide above the wheels, however the sportside tapers more to the rear, almost a full foot difference. Could that factor in when considering aerocaps? Maybe swap to a sportside, and smooth it out some? [[Page 31 & 34 on PDF]]
Also: Our generation (94-97) have different front ends than the 98+, but to swap fronts between generations you can change out the radiator support and it'll all bolt up (hopefully). From a side view, the Isuzu front end is
significantly more slanted, and the S10/Sonoma/Bravada fronts are snub-nose. [[Page 27 & 28 on PDF]].
I understand low-cost is your goal, but maybe... just maybe... it's worth checking?