Looking For 95% + Efficient Mobile Home Furnace - Top/Side Return

Anyone know of any mobile home approved 95+ gas furnaces models that are set up for top/side returns ? I'd like to fabricate a duct board return on the side wall to get it more to floor level and add use a return grill that holds a real filter. The current furnace is a Miller oil with 75k in/68k out. The calculations listed under the electric panel show 67,500 btu needed so the furnace size seems matched pretty good. I figure the heat loss underneath plays into keeping the plumbing warm. Thanks and God bless