DIY 48"x80" flat pocket door

Finishing an attic and looking to use a large pocket door for the bedroom. I want it to be flat with no visible fasteners besides the finger catches, like a hollow core or slab door, but it will need to be 48"x80". I was hoping I could just glue two sheets of 3/4" plywood together and call it a day but it seems like that will warp. I'm now between two options: either build a basic frame out of pine 2x4's and glue 1/2" sheets of plywood to either side, or try to glue a 1/4" sheet of plywood to either side of a piece of mdf. I'm leaning towards the pine frame as it seems easier to accomplish than a big glue up and the sliding door hardware would be more secure. Please let me know why both are horrible ideas!