The are a few options here, but at the end of the day what sort of $$$'s do you want to spend.

Yes, Denco are a good local option (in CHC), when I checked them out, Denco actually use "ross" blanks & machine to suit, Denco market them under there own name because they can't use "ross" - "ross" don't have any say on the quality of the finished product, so won't allow them to use their name for the finished product.

Ross, JE and Wiseco are all available ex the USA and they will all machine & finish to your spec, They're also all priced simular its just the importer & their cut that makes the difference this end.

There are also factory (cast) psitons available that are easily machined to the right spec i.e only very minor difference's - mazda 808 comes to mind.

suggest you decide on a budget & go from there.