No space? No problem. The city should condemn several blocks of Hollywood mansions and take the land under eminent domain. Big government is just a boogie man until they actually take your property or life.
Good start. What the authorities could do is institute a maximun lot size so no one has more land than anyone else (after all, that would be fair). Then take seized parcels whcih are contiguous and build public housing, and for the smaller parcels allow mini-houses, RVs, tents, or a mix. We must have housing that reflects the community.