Welcome ...

to get you on the way with your task check this threads:

http://www.bdsmlibrary.com/forums/sh...ghlight=collar

http://www.bdsmlibrary.com/forums/sh...ghlight=collar

http://www.bdsmlibrary.com/forums/sh...light=contract

after that there is search option as a part of the bar here ... try with collar and contract - she what comes up ...
also - Google is sort of deity keywords BDSM contract, Bondage & collar .... etc.

The most important thing, this being the deal between you and your husband is that you both find what is important and meaningful to you! no "of the shelf" ceremony will cut it as much as something that you really desire, and that you (and him) do from your heart.

good luck