Wow, they really go for a lot of money?
I got 3 of those. Of the ones in the first picture, I have a purple and a blue one.
Of the one in the second picture, I have a black one.
And no, it's not the Sega Sports black one. It's the Japanese black one.
And if you're wondering why I distinguished between the two pictures,
it's because the first picture is of 3rd party shells while the second is of an official Sega.
The Sega ones came with a Dreamcast sticker and had SEGA printed on the front.
They also came only with the top half of the shell.
The third party shells require you to switch the top and bottom,
because the top is not compatible with the Sega bottom.