Have you given consideration to try PET ? It doesn't warp, it doesn't require a 110°C heated bed, it doesn't smell (as much), it melts above 85°C which is probably OK for whatever you have in mind...
The Printrbot line has 3 products : the Play, the Simple and the Plus. They used to be in wood, so when they shifted to metal contruction they named them the Metal Plus, the Metal Simple...
The Plus has 10*10*10 inch volume, the Simple is smaller but you can upgrade the Z and Y axis with some kits so I think you can reach 6*8*10 volume. I'd say both are interesting for you.