Hey MTFBWY, no I actually didn't make one yet! It was at the front of my mind at Musikmesse a few years back, I was twisting the asian pickup and hardware manufacturers left right and centre to try and get hold of the chrome pickup mounts to make it work.
I was never fully satisfied with the design from the OP, not that it's bad, but as Rosie has demonstrated above with her adjustments there was always something not quite right about the Jag style bass horn, especially on the one with the Rickenbacker 4000 style pickguard. Just too much negative space up there and the non-radiused edges make it look even more bulbous and rounded, which doesn't really fit with the very svelte lines of the lower body.
It looks good the way Rosie has it with the Rickenbacker style horn, which is great for that guitar (and I'd do it that way on request) but for me, I'm always judging these sorts of designs as a successful hybrid between several styles and it just tipped it too far into Rick territory for me.
Though I have since incorporated more Rickenbacker style design language into other guitars like the tailpiece ramp
if I were to do a Rickenbacker style design from here I'd probably go with the Rickenblaster design a few posts above