@mkirsch. Yes your low mile 8.1 is a real gem. GM really screwed up by not continuing the LS/Allison combo. Even if not the 8.1. They would have OWNED the HD pickup gasser market for many years. Only ones close up until just a few years ago was superduty gassers once they got the 6r140 trans in the early 2010s.
But to your point, older trucks like yours and any other good examples are fetching top dollar.
And for a budget minded purchase like the OP is after, even if the 8.1 is top dawg, it’s imo more about the overall package and value.
And with them not getting any younger, any less miles, any less wore out and any less rusty, finding a suitable truck with minimal miles, wear and rust AND not 25 grand is the name of the game.