Geoffrey,
This topic has come up here before, and several folks have touted the
Tallman orchard ladders as a primo product - http://www.tallmanladders.com/ I've not priced an orchard ladder in several years, and while they're
probably fairly pricey, the cost probably pales in comparison to what
a trip to the local emergency room or orthopedist would set you back,
if you took a tumble off of a typical stepladder, or out of the tree.
There may be other manufacturers of similar products; I'll be
interested to see additional responses/reviews.
Lucky Pittman
USDA Cold Zone 6
AHS Heat Zone 7
Hopkinsville, KY