Hi drumster,
The bank I work for (Lloyds TSB) allows you to transfer any balance on to your credit card that you wish to. If it is someone elses balance, then so long as you give consent to bring that balance over on to your credit card, they will do so.
So to answer your original question, the answer is yes, so long as your wife calls the bank and passes the required security questions, and then gives her consent to bring your balance on to her credit card.
I don't know if the same policy applies to every other bank, but I would assume so. If you're in doubt, a quick call to the customer services department will soon answer your question.
Hope this information is helpful.