In Australia I think you will find squillions of Pentax, Nikon and Canon cameras. Other brands are there, but their market penetration was nothing compared to these three in the seventies, eighties and nineties in this country.
Canon AE1
Pentax K1000
Nikon FM series, any of them should be alright. FM, FM2, FM2n, FM-10 and the latest derivation, the FM3a. These cameras have a light meter built in, but their shutter and everything else is completely manual. These cameras will work without any batteries. This range of cameras was introduced in the mid to late seventies.
The sister camera to the FM range was the FE range. The FE range had electronic (the E in the numbering name) to help the photographer. Essentially the FE range differs from the FM range in that the shutters are electronically controlled. A flat battery and basically apart from one mechanical speed, these are dead.
The FE was the last camera Nikon produced for the amateur that can take all lenses from 1959 onwards. The FE2 camera (I’ve owned one of these from new) cannot take lenses manufactured before somewhere around the early seventies. This is not a problem as the amount of Nikkor lenses available (Nikon’s name for their lens range) is astounding.
The Olympus range of cameras are terrific, but their prices are usually way too high for me to see them as reasonable value, let alone good value. The Olympus range of OM cameras like the OM1, OM2, OM3 and OM4 and their variants were, in most cases, filled with ground breaking technology, either in clever flash technology, or clever miniaturisation of the camera as a whole. In short, the OM range were a breath of fresh air. The amateur range of the Olympus cameras were the OM10, OM20, OM30 and OM40.
If you have small hands and find cameras heavy, then the Olympus range of cameras could probably be more suitable for you.
Where in Oz are you? It is possible that there is someone near you that may read this and they may have a suitable camera just waiting to be matched up with you.