The Russel Denholm mould, sometimes referred to as "Fay" is regarded as the best within the rules and what all new composite boats have been produced from for a fair while. Phillip Warren-Smith is who you contact for more info on buying a new boat (link on mozzi wbsite)
Irwin is widely regarded as the best & most common brand for mainsails & spinnakers, while Goodall is used by top competitors as well (it's a more powerful sail)
As far as foils go there is alot of personal preferences but basically there is a trend for more high aspect foils with tapered trailing edges. (most are older generation A class stuff)
Mast is available from the association and is slightly softer and lighter than alot of the older boats.

That's fairly brief so feel free to ask more