Just google “Duotone daytona”. The complete hydrofoil is sold 3000€ or 3600USD 
I don’t think that this mast exists as a spare part. Therefore the idea to DiY one see below.
This mast is part of the Duotone Daytona race foil:
Mast: 1.05m long, 2.39kg. A 90cm one would weight around 2.0kg. Not bad.
Pictures taken from Foil Boarding: Duotone Daytona Race Foil Review | Action Sports WA
Using 10-15 layers of fabrics, It should be possible for a skilled DiYer to make such a monolithic mast in one shot, either around a mold that looks like this mast + vacuum/infusion or inside a 2-part hollow mold plus a compression bladder.
Other possible building technique: New build from 3D printed molds (very low cost, but high performance !) - Builds - FOIL.zone