Pora, have you seen Bravissimo,
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They cater specifically for ladies to whom the Bosom Fairy has been generous and, although they don't go up to a size 48J, they do at least photograph their bras on generously-endowed women.
I find Freya bras very comfortable, particularly FY41 and FY14. You can't see the seam in the lower cup of FY14, but it's in the same place as FY41. I reckon you could pare down the top of the cup of FY14 to give a much more revealing bra without loosing support.
On the subject of fitting: like shoes, every manufacturer has a different idea of sizes. I've been told that La Senza's fitting policy is to sell a bra, any bra, rather than loose the sale, and their fitters are told that if they get the largest cup in a band size and it's too small, they should just keep going up a band size until they find one the fits the cup even though the wearer can practically turn round in it. I know this is also true of Victoria's Secret in the US: my skinny UK-size-10/US-size-6 DD was told she needs a 36D there. Ridiculous! Bravissimo put her in a 30E and it fits perfectly.
I like Bravissimo (can you tell?) and if there's a shop near you I suggest going to have a bra fitted. You may find that your band size drops significantly.
I just had a look at the larger sizes at
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and, hmm, they are rather... err... functional, aren't they?
Underwires: just thinking laterally, has anyone tried cutting underwires from flexible plastic such as milk cartons or slightly heavier? It's easy to cut and you could smooth it with sandpaper. If you put the flat side against the body it would curve around the body but not droop. If you use something like a Flexicurve you could make custom-fitted underwires that replicate the shape of the underneath of the breast perfectly by actually tucking the Flexicurve in place and removing it without changing the shape, and a slightly tear-drop shape would give a rounded end under the arm to give more support and less inclination to poke.
Sally