If you have excellent material (very stable, flat plywood) it's possible to make cabinet doors with it. There is a point at which the size is too great to use plywood; it would be advisable to use frame & panel doors. You see the warp in plywood is exacerbated by the increasing size of the door. You could certainly have veneered lumber-core doors built, or possibly veneered MDF, but with a heavy MDF door (weighs a good bit more than lumber) combined with its inherent screw-holding weakness becomes another obstacle which lumber core doesn't suffer from.
Casey

If you have excellent material (very stable, flat plywood) it's possible to make cabinet doors with it. There is a point at which the size is too great to use plywood; it would be advisable to use frame & panel doors. You see the warp in plywood is exacerbated by the increasing size of the door. You could certainly have veneered lumber-core doors built, or possibly veneered MDF, but with a heavy MDF door (weighs a good bit more than lumber) combined with its inherent screw-holding weakness becomes another obstacle which lumber core doesn't suffer from.
Casey

Thanks a lot sombreuil!!