Perhaps straying too far away from a "camera" but had you considered a mobile phone ?
Motorola W377 (pink) under 25 quid, is a VGA quality mobile with 10 MB of internal storage (enough for 250 to 500 at a guess) with Bluetooth and USB for transfer, rechargeable battery lasts 400+ hours on standby, weight under 100 g, has FM radio (and if you bought a 5 quid ASDA PAYG SIM you could call the phone to find it if it got dropped in the sofa or wherever.
Flip style phone so when shut it will not make phone calls, camera function really easy to use... on mine I hit right button to go into camera mode, then left to capture a photo, then hit left again to store, and choose "store only" (rather than sending it in a message).
Possibly not what you were thinking of, and clearly not camera shape, but a fairly sturdy
case, small enough for a child's pocket (compared with a bulky camera shape).
Just an idea, and of course no need to get a pink one (just thought it might make it less likely to be considered of interest by boys attempting to steal it, even if they don't know this is not the latest in phones).
Design came out perhaps 2-3 years ago, and mine still going strong from purchase 18+ months ago.