I think your idea is interesting Chisel, but if I were the big man, I would go in a different direction. With the recent posts about people scripting coin-run bots/scripts, your plan may be punked by these masterminds!
All items are evaluated, and items that are better than basic mid-level eq (primes > 4d4, Non-body +stat, all dams, all heals, etc.) are on a different timer system. The basic eq of the game can stay on normal timers however they are. When i proposed this idea on a different forum, some people bawked and said that this doesn't favor the weekend player. Therefore, some of the mid to lower end eq could be left. The people who play 1-2 hours a week could find these type of items and not have to worry about them decaying in rent.
Idea:
For example, +dam boots' decay timer from Irda would work as follows. From the instance the boots are popped, the boots get 3 weeks in peace/rent. Every tick the boots are rented, inned, or in a peace room, the 3 week decay timer is ticking. Every tick the boots are in non-peace/non-rent rooms, the timer is not ticking.
This prevents the long-hated deeprenting problem. This prevents people who know that items are rent decay from logging their char on and inn-sitting to prevent the decay timer from ticking. It also rewards players for "playing" the game and not sitting in the inn or leaving your char on overnight spamming skills with a lucky bone charm on (no one does this do they? Only Tiger gets deleted for doing this!).