Peter - and anyone else that is interested...
I received my bent plate bridge yesterday and installed it on my LG5 fretless. I am very pleased with the results. The bass lost none of it's "mwaah", in fact the action could be lowered a bit and I have at least the same "mwaah", maybe even a bit more. The rather sharp attack of the ebony board has been attenuated, and the instrument is now "nicely articulate" as opposed to "sharply defined". The upper mids no longer have a dipped response. The sound is definitely still punchy, and has that nice naturally burpy front pickup sound. There is still a nice response to different attacks, but the LG5 is a little less "touchy" about them. The bass is also less noisy when favouring one pickup over the other (I did not expect that). Overall, my LG5 now just sounds older, warmer, and more organic (a goofy word to use, but strangely accurate).
Peter, I think you'll find that the vintage bridge goes a long way towards where you're headed, combined with the right strings. I'd recommend Fodera Wooten nickel strings in light guage (.040 - .120), but I'm sure someone will be along in 5 minutes to slag them for being too expensive.

I disagree, those strings are magic with Jimmy's basses - particularly the 5 strings models - and well worth the higher cost... IMO.