If you're on FB, post it on the Rickenfakers forum.
I've got a Retrovibe bass and also their bass pickups in the bass half of a doubleneck.
I have to say I kindof pooped on David's parade when he said he was doing those LP basses as an example of putting Ric pickups on things and I posted my Rickenberger...
Northern Guitar Show postponed, F1 postponed, footy postponed - shame for the folks relying on them or looking forward to them.
My train in to work today, which is usually rammed with people standing had at least half of the seats empty.
I think if you're going to copy the body shape then you might as well go with it for the headstock too (subject to trademarks...).
If you're going to get more radical, then do a coherent style across the whole instrument.
(IMHO, of course!)
I've never played one (a Ric 5-string), or even seen one; I'm sure it'll happen some time.
I do quite like added flexibility of a 5-string though, so it may just be a matter of time.