If you were having a flute custom made for yourself, and you were going for your “ultimate” flute, what would it be made of? And describe the ideal sound of your ideal flute.
Cocus and sterling silver! 
The tone is bright and the notes have a pop to them…
Ytterbium with Yttrium. The notes would have a ytterbic pop to them. “Y”?
Unobtanium, of course! Unobtanium has the ability to sound just how you want and any time under circumstance, practically plays itself. 
Borium with Tedium is my runner up.
18/10 stainless.
Yes, I am that boring.
Upsidaisium would make a nice lite flute. 
But then you have to deal with meddling squirrel and moose.
I thought everyone knew that Diddle Didee wood, though very scarce, has been known to impart the best Irishy sound of any tunewood.
Clinton
It’s not the wood, it’s how you cut, tap and roll it.
I’d go for Mopane for the easy care and then I would encrust the whole thing in pave diamonds and randomly placed emeralds, rubies, and deep blue sapphires. Nothing is too sparkly for me.
Holly ? Box Is lovely. With silver fittings . Maybe a fruit wood ? But not Yew for obvious reasons.
I’d like to have Rose Wood and Rudall Silver…yeah! and a beer please! 
I made a flute from Holly, very light wood, you need to seal the bore. Also, wear white gloves when you are playing it, to keep from getting finger prints on it!
oleander with lead lip plat (in case i’m allergic to the wood), rings and keywork.
Ooooh! That would be a killer flute.
African black is losing favour to mopane, modern cocus etc but it’s hard to beat.
African black wood & silver please.
ABW&Silver H&Mc prototype - D reel
For the sound probably blackwood, or a more reddish wood with the same sound. And silver.
Cocobolo with carved lip plate, sterling silver rings and keys on posts not blocks.
I’d also love to see a flute made of Tulipwood.