Could anyone suggest a list of things I should check for in store when I buy my V1 to make sure the unit doesn't have any problems?

Thanks in advance

Simply put, it should be in a sealed box, from a reputable dealer. If not, check the hours meter...and then work off the menu.

I was trying out a V1 in store, and something weird happened when I played around with the shutter speed. Inside a room with flourescent lights, thick, brownish lines appeared across the screen when the shutter speed was over 60. The lines became more obvious the higher the shutter speed. When I took the camera outside into natural light, the lines disappeared. Does anyone know what could have caused these lines?

That is an odd symptom. There can be flickering issues with fluorescent or LED lights as they operate at frequencies that can become disharmonious with a camera's speed. Most fluorescent lights these days are now operating at such high frequencies that there should be no artifacts. I shoot with compact fluorescents and have no problems. I'm not sure I have tried high shutter speeds with my V1 yet. If nobody else reports, I can probably try it tonight and report back later.

Thanks for your reply Marcus - I'd be interested to hear if your camera has the same problem.

It is true that the lines were more obvious at higher shutter speeds. But they were already visible at 60, which isn't high at all. The camera was in 50i and everything else was on automatic... the lights were just normal flourescents found in offices and shops. The lines I saw were not flickering - they were strong, thick lines that moved slowly down the screen. I tried out the Canon A1 in the same lighting situation, and it had no problem at all dealing with it.