After much searching, there are no aftermarket lines to be had. The 8.1 in the Suburban is a different installation than in the pickups, and sometimes parts are hard to find. Items that are generic to the 8.1 are generally easy to find and have good aftermarket choices (VistaPro Radiator for example). But some items that are specific to an 8.1 in a Suburban don't make it into aftermarket inventory because the demand just isn't there. Both Dorman and Edelmann make trans cooler lines, but not for this application. Engine oil cooler lines, yes, but not trans cooler lines.
Sooooo.....bought the Delco lines from Rock Auto at $13 each. Installation at the trans doesn't look too bad. Removal of the lines, the shop manual indicates using a pick to pull out the wire clip, the caveat at doing it this way is that the clip must then be discarded. I am headed out of town so hopefully will dive in this weekend when the parts start to show up. Will keep you posted.