Thanks for the tips...sounds like there are LOTS of options out there. I like the idea of building something myself, but I think my best bet (since I have no carpentry skills and neither do my brothers!) may be to save up for a kennel of some sort. I DO have a side door (the one in my picture), and that spot is probably the most logical for putting a kennel if I end up getting one. There's a big bush there that would need to be cut back / eliminated, but I should probably do that anyway...so not a big deal.
Regardless of whether or not I take on Fritz, I think I should plan on doing this at some point, anyway. Fiona makes it through the day and Fritz would too, but I'm sure they'd rather be able to go out when they need to - and it would make my life easier, too! I could just let them out when they had to go instead of digging out the leash and standing over them...
Well, there are lighter weight mesh fences that are out there too, that you could figure out how to put up... keeping doxies in does not take bull-strength mesh... Something between chicken wire and hog panels ought to do the job, and could be set with ordinary posts. The cover issue is mostly for the cats. The cats are the escape pickle.