could you say that town is homelessnessless?

Has. The word is legit, but it would be an adjective because of the last -less there, so:

• That town has homelessnessless.
• That homelessnessless town is nice.

You could convert it back into a noun, through zero derivation; for example “homeless” is an adjective too, but people can say “the homeless are hungry”, as if it was a noun. But it sounds weird in this situation, I don’t know why.