The only swinging hinge style I _haven't_ run across on ebay (antiques/architectural/hardware category) is the one that mounts in the floor. That would be the hardest to replace; I guess they are always overlooked by the wreckers. The kind that is cut into the bottom corner of the door is easy; it's still being manufactured.
Casey

Thanks! Yep, sadly the floor-mount type is indeed the kind we have...ah well! :) One of the two hinges sold by HoAH is a pretty close match for the size, though, so we think it will be feasible to retrofit it to the door/floor by filling a section of the floor (and maybe the door too, though fingers crossed that the fit will be close enough there). We have a really crazy floor situation where it was actually mounted to the fir subfloor *before* the oak floor with inlay was laid around/on top of it---so it was quite a feat to get the door down to begin with (though the flip side of that is that I suspect it's why the door was still in the house at all---too much work for past owners to get it off!) I ordered that one to test out and see, but was curious to know if anyone had experience with it or any of the others (or good advice on retrofitting!)

BTW, just in case anyone with a similar problem finds this---the HoAH hinge turned out to be a near-perfect fit for our old floor-mount hinge, and we got the door re-hung with just a tiny bit of floor-filling and door-cutting. Practically perfect! The only glitch is that the modern hinge stop points are a few degrees too far for our door to reach, but luckily it has two---so it stops just shy of 90 degrees but doesn't reach whatever the next setting is. (Old hinge stopped at 105 or so, I think, and was a perfect fit for the space in the house.) But on balance, this was a great solution for retrofitting an old door and the hinge seems like solid quality.