[semlar]

This appears only capable of using the player's gender, but I'll leave it here anyway..

local RaceIDs = {
    Human = 1,
    Orc = 2,
    Dwarf = 3,
    NightElf = 4,
    Scourge = 5,
    Tauren = 6,
    Gnome = 7,
    Troll = 8,
    Goblin = 9,
    BloodElf = 10,
    Draenei = 11,
    Worgen = 22,
    Pandaren = 24,
}
 
local dum = CreateFrame('DressUpModel', nil, UIParent)
dum:SetPoint('CENTER')
dum:SetSize(300,300)
dum:SetUnit('player')
dum:SetScript('OnUpdate', function(self, elapsed)
    self.e = self.e and self.e + elapsed or 0
    if not self.race then self.race = next(RaceIDs) end
    if self.e > 0.8 then
        self:SetCustomRace(RaceIDs[self.race])
        self.race = next(RaceIDs, self.race) or next(RaceIDs)
        self.e = 0
    end
end)

The closest I could get to swapping the gender was getting the correct gender model with the player's gender's texture which lead to some horrifying results.

*cough*