Can I melt Barium Titanate powder into a cylinder and preserve the high dielectric?
As you know, barium titanate is a piezoelectric ceramic materials. It has its property as a piezoelectric material due to the specific spatial arrangements of its constituting atoms. Melting this material, means that it will lose its crystalline  structure upon heating (knowing also that its Curie Temperature is $T_C=120^o\mathrm{C}$, i.e. above this temperature it loses its ferroelectric property).
On the other hand, processing and shaping ceramic materials are often performed during the preparation of these materials, not after. Heating at temperatures around $T_C=1600^o\mathrm{C}$ for processing ceramics is not a common procedure and it is expensive.
If you want to prepare cylinders and discs from a powder of barium titanate, you can add it to a polymer matrix (wax, epoxy resin,..) in an appropriate mold using adequate processing techniques like injection molding (heating below Curie Temperature). Of course, the resulting dielectric constant of the composite material is less than the one of pure  barium titanate.