I would stick with 27" also. And used wheels can be a bargain. Just make sure they are straight.

Another option is to get a pair of 27" rims and transfer the spokes over one by one from your old wheel to your new rim. Its a good way to get into wheel building. Just loosen all the spokes up first. Then lay the new rim against the old rim. Line up the valve hole and start transferring over the spokes. Put the "new" wheels in the bike and tighten up the spokes using the brake pads as your trueing stand. Make sure the rims are centered between the fork blades and stays. I did this recently with a pair of vintage rims I purchased on ebay. About $40 shipped for vintage Weinmann rims. Unfortunately the rims were not perfect, from sitting around a bike shop for 40 years, but much better than my flat spotted original steel rims. Took an afternoon to accomplish the task. A good 4 hours of labor. Been riding them for a couple hundred miles and they haven't needed any trueing.