I want to make some ubers practice for the next ladder season and I want to do a few runs with the cheapest (in terms of new ladder prices) yet effective smiter build possible.
What would it include?

Gface, black, spirit, treachery, goblin toes? What else?

I personally used lionheart but treachery is prob better.
life tap wand
4os pal shield with perfect diamonds
soe/100life belt

Prebuff with treachery for +60@ vs Meph

and then swap with? lionheart? Do I even need to swap?

Some ideas here

Google poorman's uber trist

You can do it with full iratha's.

Use Iratha's.