Perhaps you could adapt the idea of this Hometalk member who turned old windows into a pergola:
@Susan Landry - There are a number of sites on the net that show you what can be done. Some you will have to contact the poster of the picture for some instructions. Just google 'repurposing windows' and it will bring up lots of sites. Here is one pic I find particularly interesting - http://www.houzz.com/user/moorekidz - they call it a greenhouse but a building is what you make it, there is a lot of eye appeal in this one.
Susan ~ there are tons of recycled window greenhouse examples on Pinterest. Have you looked there?
Susan - check out the examples on this link http://dishfunctionaldesigns.blogspot.com/2012/12/greenhouses-made-with-salvaged-windows.html
Susan, using these windows for this is a great idea, many people make all sorts of plant growing rooms with them.
The only thing I will add to this great idea is that the older window frames often contain lead paint and if still puttied with old glass may contain asbestos in the glazing compound.
So when cleaning them up in prep for paint be sure to do this work over a plastic drop cloth, not cloth type. And be sure NOT to use a heat gun unless your wearing a mask that will prevent the possible lead fumes from being breathed in. You can test the paint by cutting into it with a sharp knife that reveals all the layers of paint then using a lead paint test kit found at all paint stores and larger home centers test that spot. If tests come back without lead then a simple N-95 mask will be fine when you clean up the paint in prep for new coating.
The reason for the plastic drop cloth instead of the cloth type, is that lead dust can become trapped in the cloth types and easily brought into the home. While the plastic types are simply discarded once your done.