There are lists of pet friendly resorts on the web. It's hard to know if any resort found there is still pet friendly. I know the Westgate Williamsburg, Gatlinburg and at least on each in MB & Branson are pet friendly (or were a year or so ago). Normally Westgate's are but it's resort by resort and not listed as such in II. There are a couple in Orlando.
http://www.redweek.com/timeshare-attractions/pets-allowed
http://www.sellmytimesharenow.com/timeshares/index/content/pet-friendly-timeshares/
http://www.tugbbs.com/forums/showthread.php?p=598672
http://www.rci.com/RCI/RCIW/RCIW_index?body=RCIW_KBResultExpanded&type=help&id=85
II show's 158 resorts when you search but I know that some listed don't allow pets and some that do aren't listed.
Even when they allow pets, it's not always that simple. Sometimes it's only for owners, sometimes it's only in certain units/buildings and often there is a fee.
ASAMOF, when you used to search II for
DVC (when with them) there were times when some of the DVC resorts would make the list as pet friendly.