Not sure what you want this for, or how accurately you need the strips, but have you thought of buying rolls of paper designed for printing receipts and/or adding machines. I've certainly seen them about the width of half an A4 sheet in cut price stationer's shops.
I suspect they will be 100mm wide, slightly less than half the width of an A4 sheet.
Perhaps cutting these to length might pose less of a problem? Just a thought.