Problem with reconing etc is that I'd have to send the old driver to someone like Wembley loudspeakers (£10), have it reconed and voice-coiled (about £120) then have it sent back (£10). It was always underspecced for my amp anyway, rated at 200W - 300W of Marshall clipping proved too much for it.. And it would still be rusty!
So it may not even have a magnet big enough for what I want either (though it is a 4")
Multiple drivers isn't an option, nor is 10" and 18" as the folded horn cab I have is for a 15" speaker (not that I ever liked 10" or 12" bass cabs, they always seemed too Mark King twangy rather than Bob Trujillo rockin')..
I'll look into RCF - to tell the truth ultimate fidelity isn't what I'm looking for, I've got DI outputs on my bass, effects unit and amplifier should I need a really clean studio sound which is unlikely as round here they're all bleedin' folkies!
And I've just checked Wilmslow Audio - their drive unit prices aren't for the faint hearted. The Volt I was looking at for £250 on a pro website, without even asking about trade, was about £320 at Wilmslow...