Just as it sounds, an option on the DMAP editor to set that DMAP's graphic for the LSK. The display in ZQ would still use whatever you have set as the default graphic, and that graphic would be used for DMaps with no special graphic set.
Set Level Specific Key graphic at DMAP
Cool suggestion. o.o If worse comes to worse, you can have your LS Keys in Cset 9, so the appearance of the key will change per each Dmap. It's not quite as good, but it's a start, and it's possible now.