On eBay I found some plastic 5th Edition Bretonnian horses, one was badly painted but had the metal horse head and legs of a Knight of the Grail. The paint was so thickly caked I thought the plastic wold be a total loss, but the strippers I mentioned broke the superglue bonds to the metal pieces and after a week in LA's Totally Awesome, the plastic horse scrubbed back to bare plastic. After some smoothing with scalpel and sandpaper, it's in line to be re-built and once again carry a hero of the Lady to war.
Last year I found a broken, awful paint-caked 4th Ed. High Elf Prince Tyrion for cheap, thinking I could salvage at least the metal rider and horse head, and so I have. But even the poor Caparison horse body stripped well and the combined cement and superglue were weakened by stripper and freezer, and the thing is going to be rebuilt as well.
I ended up putting the metal Prince - with a plastic sword added as the original metal one was broken away - and horse head on a plastic 5th Ed Bretonnian horse, as Tyrion's horse Malhandir is stated to descend from "the Father of Horses" and it looks good as the slightly bulkier Bretonnian-style charger. ( In lore Bretonnian warhorses descend from breeds used by the Elves of Loren) And I have Prince Tyrion for 1/3 or less of what nicer copies are going for over here.