The packframe plan in the '60s BSA FIELDBOOK looks rather like a ladder with the sides "angled in" toward the center. - The 2 plans have:
1. one "boy-size frame" that is 24" tall, 12" wide at the top & 18" wide at the bottom
AND
2. An "adult-size frame" that's 36" tall, 18" wide at top & 22" wide at the bottom.
(In my "mis-spent youth", I "packed in" a 75+ pound, cast-iron, woodburning stove on the BIGGER model to a "sub-camp" in SE OK.)
BOTH sizes are NICE for packing "odd-shaped" & bulky loads.
yours, satx