Gutted my basement (Minneapolis/St. Paul) and now in the process of building it out. Definitely building a bar, but not sure if I'll recoup enough money on adding a sink to make it worth while. Upstairs bathroom is overhead so supply lines (galvanized) are right there along with the drain line. Hard to say what the easiest route would be to tie in the venting. I'm told ventless pumps don't pass around here (Minneapolis/St. Paul) so busting up the floor seems to be the only option to drain the sink.
Across the way is this lovely unvented bathroom. (I've got a one story and there's a closet above so running a new vent up through the roof would be relatively easy). The goal would be to make it a legal bathroom or in other words start over from scratch. I can do the drywall and carpentry and really just need the plumbing expertise to tie everything together so it is code compliant.