Not to go off-topic, but there have been times and hubs where 20 minutes was in fact the domestic-domestic minimum connect time. (I'm recalling a few years ago at CVG, specifically.) It may still be today - it's plausible, though too risky for me - at MEM or SLC.
edit: I see the OP's LAX-LAS-SLC route is bookable today with the 20-min connection.
Last edited by 3Cforme; Apr 23, 2010 at 7:29 am