well i can give you some specs, i am using 2 CREE downlight globes available from jaycar, each globe has 3, 1 watt cree LED's, the only killer is that each globe retails for $60 (however my brother is the manager and wants some CNC work done so these 2 cost me nothin....)
the housing is custom made, aluminium front machined to fit the lights with polycarbonate retaining rings to hold them in, front has a 15 degree bend to get more spread.
back and sbottom are also machined aluminium and the top and sides are a piece or formed polycarbonate so i can see inside the box.
i could have gone with the widely available plastic headlight that fits downlight globes but it would look **** on a z50.
the bike has a lifan 110cc which comes with a full charging circuit, it produces about 1 amp when running, each globe uses about 300 milliamp, so i can happily run all night and not get low battery, i have a little 4 amp hour battery fitted to the bike so even with the bike not running i could have the headlight on for about 6 hours before it is flat.