you can buy a cheep windup radio and scavange the wider from it
this is used to partly run the lamp + charge the battery
the battery uses a dc to dc converter
to run a bright set of leds also as a lamp as well as the radio
and the battery inside is two cells 3.0v total 1.5 each
but not in series instead the load is shared accross a network
with the -ve and +ve needed by the converter
it is in an epoxy block and has no makers name or markings
{looks factory made}
so i guess this is the
bit of it thats a little harder to backward engineer
however dosnt stop it giving up to 1amp at 12volts
enough for quite a lot
the winding mech is main spring based
and easily replaced by a wind assisted drive or another 6v dc motor
i found it in maplin electronics here in the uk
look around youll find them in the local electroincs hardware shops
like maplin
take a look at there site you may be able to find this
www.maplin.co.uk