Personally, I would stick her under a sheet. Now, a nice sheet, perhaps 2000 or so thread count, but a sheet none the less. Cut out a hole for the head, stick her in and pop a veil on that masterpiece, and you've got yourself a fine, humble wedding dress. I'd also suggest sticking her in a white-sleeved shirt underneath the sheet, and cutting out arm holes.
I once knew a bride who was going this route, and she didn't cut out arm holes. The sheet was too long, and as she stepped down from the altar she tripped and knocked out a few teeth, among other things. Also, she ended up falling in such a manner that the guests in the front row ended up tumbling like dominoes. The total injury count was three broken fingers and toes, and $72.36 worth of lost purses.