Ars Magicana is a relatively popular base. If you you want an actual building to take over, the cursed abbey is large and has its own teleporter pad.
I had chests upstairs and down in Joram's house, then later moved my home base to the council hall (screenshot 32KB), to take advantage of the health/mana shrines while they still worked, as well as the additional room.

home base
Setting up "home base"