@jenkshields Honestly the lowest cost approach might be to use bluestacks on a laptop and plug that to a projector or a normal display tilted at 90". Add some cardboard bezel and you can have a "big android phone".
The projector / screen still costs but those should be easier to find for PCs than smartphone oriented stuff. 
@polychrome yeah, I did think about bluestacks! We've got the projectors already so it'd definitely be the simplest option I think.