Le Meridien Dubai offer day-use rates.

http://deals.lemeridien.com/Le-Merid...SOP_US_MD_1893

Also, if you book a hotel through Emirates Stopovers (your local office in most instances), many of them work on a 24 hour basis (from time of check-in). I have previously done this with Novotel World Trade Center. (check in at 5am check out at 1am).