Breezer Downtown 7 Step-over? MSRP $699. Comes stock with 700x35 tires and fenders, don't know what the max would be. Not disc brakes though. Not sure Breezer makes any discs.
I don't think Surly offers a stock Straggler build with flatbar (like they used to for CrossCheck), but you could buy a Straggler frameset for $500 and build it up exactly as you describe (except thru-axles)
Or if you REALLY want wide tires, how about a Krampus?