That's odd, the mushroom ring maps have always shown up for me, though they were from the zone they were copied from.
Cave systems having their own map would be really great, someday it might get done. Doing an overlay so the POI can be shared is not very easy because I can not find the original maps to pull the map information from.
I've had a few requests for ToFS maps of that damn ring below Cara. Unfortunately I'm unable to find the original map so I can edit it. What I may do is just make the lower section it's own map, because it is very easy to get lost in there.
For Bar of Brell, that would be on a lower priority list. More of a "it's nice to have a map just to have one" list. The same would go for player housing.