I have fun with borders, as you can see from these:
Cruzamento De Rio (River Crossing)
New Dawn of the West (Terrain View)
What' i would suggest though, is look through the thumbnail collection here:
There's a lot of maps with no borders, but if you skim through there you may find a few you like, then follow to the thread and check with the original author
Other than that, what I typically do is head over to google images, and type in "antique maps" or something similar and see what catches my eye.