Convertible queen sofa bed

Does anyone know where I can get the bifold queen bed sofa combo that keystone Zeppelin 241's had in 05 and the Lance 2185 has in this years model? I have the 05 Zepp. And need to replace my bifold mattress it's a 60x75 and I need a 60x80. It's 6" thick foam, encased in zipped covers. The sofa's in good shape so I'm looking for a new 80" mattress. I'll take the whole deal if need be.
Anyone know where Lance gets theirs? Or maybe a specialty shop?