On the topic of designer mutts, I sometimes think they randomly put two breeds next to each other and see if they can come up with a nice, marketable name out of that cross. That's why poodles cross with anything, because you can stick a cute little "oodle" or "poo" on there.
So there's a "logic" to the poodle mixes, even if the hypoallergenic trait doesn't always pass on . . . the logic being to have a hypoallergenic-whatever. Of course, oodle and poo sound cute too. But Jacabees are not a cross that has any logic for pet purposes . . . that's probably "cute name" (can't be cute dog, because the one I saw sure wasnt). There are a bunch of others out there that are like that . . . a cute name or a cute dog, but no "logical" reason why you would ever make that mix.