There are a LOT of variables involved. IIRC, I think a bunch of the recent new build sorority houses I'm aware of have been in the $1,000,000 to $2,000,000 range.
Some of the variables include:
Land cost (which could be higher or lower depending on region of country, physical location and if there is even land available or not.)
Type of structure (multi-floors, full or partial or no basement, handicap access, etc.)
Physical systems (furnace/boiler, hot water tanks, wiring, a/c, etc.) This can be really costly, but worth it to put in the top quality available. Also, do not skimp on electrical outlets in bedrooms!!! With the amount of electrical stuff most college students use, be as generous as possible in this area!
Furnishings (definitely lower or higher based on what you already own.) If you have to purchase everything new, you'll need a LOT! Beds, dressers, desks & chairs for 60; dining room furnishings to accomodate chapter dinners; kitchen appliances and accessories; living/parlor and rec rooms; house director apartment; and so on. If you plan to do a computer room or a workout room, then there's even more you can spend
Does any of this even close to answer your question? Hope it helps a little!