I got my credit union yearly booklet with statement of accounts etc.. recently and they had a breakdown of most popular reasons for loans, wedding loans were quite high up the list - so I think credit unions would do it. Youd really have to ask your own bank or credit union if they would be willing to loan you for a wedding.
Personally I think youd be mad to get into debt for your wedding. Im not saying you shouldnt spend whatever you want on it, but I think youd be better off saving to make the spend instead of borrowing for it. Its only one day, and my own opinion would be that the marriage is far more important than the wedding. Nearly 30k seems like a huge amount, even including big families. If you already have 8k in debt between you you are talking about racking your debt up to approx 20k, just to get married.
You cant really depend on presents to cover costs these days either. I got married myself last year, eloped and then had a party when we came home. At 100 guests we came away with less than 3k in cash gifts. Some people gave nothing, some people gave physical gifts, some people gave very small amounts (wouldnt even have covered their cost at the party). We werent looking to recoup the cost - but just the point is that its not something you can depend on.