How about plastic junction boxes http://www.lowes.com/lowes/lkn?action=productDetail&productId=10005-223-B232BUPC&lpage=none http://www.lowes.com/lowes/lkn?action=productDetail&productId=70985-223-A400-R&lpage=none . Simply cut off the nail brackets, then you could hot glue any gaps or holes