The Konica Big Minis/A4 as mentioned do have a flash off option, you can set the flash mode while the camera is off.
So if you set it to off, when you turn it on it remembers the setting.
However, after turning it off it forgets again, so you just get into the habit of setting it when you turn it off.
It's not as ideal as the Contax T2/3 options, but for me better than the Olympus MJUII option of turning it off each time you turn it on.
I have the Nikon L35 1 2 and 3, from memory they're all flash defeatable, but you do need to push the flash back down again. The 3 does away with this, and has a button beside the lens, which you press and hold in order to not only defeat the flash, but also give it +1.5 stops of exposure compensation.
The Ricoh FF3af (35mm f3.2) has a slider underneath the flash that you pull out to enable the flash, and has manual ISO settings for 25, 64, 100, 400. (the lack of 200 and 800 is a little puzzling, and they seem to move waterhouse stops behind the light meter, so it's not possible to wedge between settings.
All of the Yashica T series have built in flash, some are 2.8 and some 3.5 but they're all defeatable on turning the camera on, and all great performers.