You can kind of get married, there is the tuxedo shirt, pants, and coat that allow for a groom.  This wedding dress makes for a Bride.  The dreess and formal shirts give way for bridesmaids, best men and spectators, you can buy wedding rings from a vendor in booty bay ranging from a cheap mood ring to a ring called The Rock!  that cost 100g.  I'm sure a combination of a robe and a shirt could give the priest a collar.  There are also off-hand flowers that anyone could hold.  Theree's even the cathedreal in  SW.  I've met a few people that adventure with their fiance's and spouses.
I'm going to start looking for a priests outfit that'll give me a collar.
No real way to get married, just all the components ready for an eager WoW couple to use