I thought these looked pretty nice.
If I had a nice desk visible to anyone who dropped by, I would definitely consider one of these.
However, my desk is hidden away in a basement room, so I will stick with the small plastic storage box I picked up for less than two dollars. Turned on its side, the holes line up and can hold up to 18 whistles. I keep an old mouse pad underneath to protect the whistle ends.
(Thanks to whoever on C&F suggested this!)
I have to echo swizzle’s thoughts exactly. If I had a nice setup for my whistles, than I would gladly replace my plastic crates. 
I did a search a while bakc and saw your stands and though it was a great idea. Unfortunately, I couldn’t find them anywhere. I keep looking justin case, but no luck, yet.
Can’t remember where I picked my up, but I know it was a big box store like Target, Walmart or somesuch.