Since posting to this thread last week I've flopped and reversed the upright bars on my comfy hybrid to get the grip position closer to saddle height. Then I chickened out and raised it an inch or so to just above saddle height.

Still felt like I was hunched over for a time trial, although in reality I'm sitting mostly upright and only slightly leaned forward. Rode 5 miles the first day, 19 yesterday, and can feel some discomfort in the neck (due to a permanently damaged C2), but overall it felt better. Stronger pedaling on climbs and into the wind. I'll try it awhile. But I doubt I'll ever be able to ride drops below saddle height again.