I dont personally know of anything available like you are describing. However, just wanted to throw a thought out at you.....Have you guys considered buying a new/used mobile home and either renting a lot for it, or purchasing one? The reason I ask is because my best friend used to sell them and you could find many really nice ones (even brand new ones), in your price range and below. My friend bought one herself before she started selling them, (which is why she decided to start selling them.) The one she got was either brand new or maybe a repossessed one and had 3 bedrooms, a bath and 1/2, great room that combined the kitchen and living room ( a very large room), and a closet with the washer/dryer. Her bedroom had a tray ceiling and was quite large too. The master bath had a whirlpool tub, double vanity, shower stall, and the toilet was partioned off (like in hotels), so that the restroom can be used privately while someone else is dressing. It also had a linen closet in the hall, and walk-in closet in the master bathroom. It was VERY NICE, (and prior to this, I was NOT a person who liked mobile homes!) But, the walls in this were as thick as those in houses, and it was very well made.
Anyway, she put $0 down and had a pmt of $380 month! Then, she rented a lot in a mobile home park, and lived there for a few years until she could save up the money for a down pmt on a lot in the country.
I know this isn't what you asked for, but just wanted to throw that option out there, in case you didnt realize how affordable this option is, (or in case it just hadnt occured to you.)
Best of luck to you both! I hope you find something soon that you both love!