As I specialise in military items, I can supply WW2 German leather belts from stock in all the correct waist sizes.

(If are looking for one of the above belts, you may also be interested in the WW1 Cavalry Y-straps, as they were widely used in WW2 by F.J. units)

Given their similar design, I am also able to supply Finnish M/22 pattern leather belts,  as to all intents and purposes they are the same as the  German belts, aside from only being available in brown leather.
I am also making the M31 pattern Finnish belts: some are hand-sewn, some riveted, as per the originals.
I may have a suitable SA type stamp made up for Finnish belts if there is demand for one. 

I also make WW1 1903 Pattern & 1914 Pattern Leather Equipment belts, WW2 1939 Pattern Leather Equipment belts,

Home Guard pattern belts, Civil Defence Fireman's Belts, Australian Pattern Belts, etc.

For the 19th Century period, I am currently waiting for a supply of brass fittings to make up some Slade Wallace Buff Leather belts
(as I have a good stock of Buff Leather in stock & the tannery I sourced it from has now ceased trading)

I am also able to carry out repairs to most of the above, as well as make dedicated accessories for them.