Potential Commercial to Apartment / condo conversion lead

[Nathan Mount]

I have uncovered a lead on a commercial building, that would be prime for a conversion to apartments or condos, but it's so far over my ski tips (expensive), I'm not sure what I can do with the lead.

Backstory - last year I connected with the owner, and we had deal for a separate 4 unit, seller financed building ,that he ultimately decided to keep.  In hindsight, if he would've accepted the offer, the end term balloon payment may have been a losing situation for me with current interest rates.

Fast forward to last month, I followed up with him to see if there was any other opportunities in his portfolio.  

He told me that he has a larger, unused commercial building in the UIC/Medical District that he owns outright and wants to sell.  He's currently in the process of cleaning it out.  I toured the property with him last week, and he told me that he'd love to sell it before the end of the year,if possible. 

I told him that this was a bit larger than what I'm looking for,  but if I could bring in a contractor/developer to get an idea of what it would cost to turn the building into 8-10 units, it would give an idea of my next steps, and perhaps bring in a partner.  He said no problem, and that he would even be open to partnering up on it as well... 

So now, I'm not sure what to do next, aside from getting estimates and an idea of comps.  I have a great rapport with the seller, and he's open to ideas.   Any advice would be helpful.