Well. Unsanity used to make Shapeshifter.
OS X Tiger launched on April 29, 2005. OS X Leopard launched on October 26, 2007.
One of the first things that happened when Leopard launched for Unsanity users was that their Macs refused to boot past a blue screen. So, until Unsanity updated APE (their app that enabled their other apps) there was negative publicity and they lost a lot of sales.
Shapeshifter never made it to OS X Leopard. Unsanity itself managed to hang in until around June 2010 but folded later on.
Unsanity's website is long gone.
Given that Shapeshifter last worked properly on an OS launched in 2005 and that the company that made it has been dead for at least seven years the probability that anyone is making Shapeshifter themes anymore is non-existant.
If someone has made a theme for Shapeshifter that you consider to emulate Yosemite then that would be surprising, considering Shapeshifter itself has been deader than dead for a long time.
I might see what I can find for you later today, but realistically all you can ever expect to find now are themes that were created while Unsanity was still with us.
I have heard ZERO news of anyone making any Shapeshifter theme in the current time.
On the other hand, there are plenty of NON-Shapeshifter thememakers here on MacRumors that have created their own versions of Yosemite/Sierra. Do a search in these forums and you'll find them.