Just tried to make a few (horrible) runs in shifting passages and labyrinth (i hate you Rex!) and i just thougth:
"oh my god I would love to have that portable altar NPCs have in a subdungeon."



Why not make a portable altar? It would be useless in maps where walls don't move, but in shifting passages or labyrinth it could make a great difference, at the cost of one inventory space. Maybe it should be useful to give it a bonus, in addition to the possibility to have a boon wherever you are?
Or maybe just the possibility to desecrate twice the same gods altar would be good enough?