I think you should tell your husband to tell his coworker to make a nice home made coupon, good for one new sewing machine valued at X amount, wrap it up in a pretty box and give it to her. OR Just tell her to pick one out.
I would hate it if my husband didn't consult me on a new machine for me...that would be like me just picking out new running shoes for him...he is very particular about his running shoes and I have no idea about them. lol