I'm not sure if portcullis would still be the proper word for it, but I do know that iron gates, hinged on their sides, were used in Scotland. The have the advantage of being simpler to produce than your common tower based lowered gates. Personally I can't think of any really good reason to hinge a gate at the top. It just makes it awkward to get in and out in a hurry. With it hinged on the side, you can open it slightly and get in or out, without having to awkwardly duck under it or open it fully.