Great suggestions. I think the 'plastic' (no insult intended) cameras suggested above are good options. I have a few if them (XAs, a minox clone Voigtlander Vito c) and they are easier to throw in a pocket than the classic compact 35s of the 70s of which I also love. I have a pen half frame and it is heavier and bigger than my XA.

I used to have a rollei 35 and for me it was a bit finicky compared to these plastic fantastics! And these can be cheap even on eBay.