While I don't really have a bike recommendation, I do recommend picking a bike that has clearance for wider tires. Wider tires mean lower tire pressure, more comfort, and lower rolling resistance.
I have a Diamondback Haanjo 4 and a Poseidon Redwood. Upgrading the Haanjo from the stock 38mm tires to some 45mm Panaracers made the bike feel so much better. On the Poseidon I swapped to a 700c wheel set and put on some WTB Venture 50mm tires. Both bikes are super comfortable now.