enclosure project...

Thanks to Connie for bringing exercise pens to my attention. I'd seen them before but never used one. I'm heading out to research them more tomorrow. Price is an issue, unfortuneatly. Mom's house has a sunken living room with windows looking out over the back patio. We've decided that those windows are the prime location for putting the enclosure. I like that the pens come with anchors. The diameter of the pen isn't as important to us as the height. I'm wondering if there is a fairly simple, inexpensive way of attaching two of the exercise pens together for added height? I'm looking at buying a 48" and 24" tall eight panel pen and using 16 gauge plastic coated wire to fashion a roof. I know that chain link would probably be more cost effective but chainlink isn't self supporting like the pens appear to be. If we can get this accomplished I'll maybe try making an outdoor cat tree out of PVC here in a few weeks. Wish me luck..somehow I see next weekend disappearing right before me eyes