jds can breed with cons and salvinis,so i would say that those would be your best bet if you wanted to crossbreed your ebjd.i personally wouldnt do it cause ebjds are so pretty already,no need to change it.
I have a friend with a dempsey/Jag cross. Face and body of a dempsey, patterning like a jag, but much darker than any jag I have ever seen. Someone traded it in to my lfs with two others a long while back.