You can put Xeon in desktop motherboard like with X99 chipset. I myself recently got 22 (44 threads) core one, but for day to day tasks it doesn't make a difference and it is quite expensive. If there was a larger demand then perhaps we could see more of these.
what kind of workload did you intended to you use this beast for ? I really wish i had a use case to buy on of those :). How did you decided to go with the X99 chipset instead of the c230/c236 (traditionally used with xeons)
Mainly for making music, some plugins that are doing simulations are very computationally expensive, so it is not possible to run many instances in realtime using typical 4-core PC. So multicore cpu like in my case helps a lot with this. Another thing is that I use a lot of virtual machines for my work, so it is handy to have when launching a lot of them etc. You also get the benefit of having more memory slots available.
In terms of X99 - I had i7-5820K cpu which I was maxing out all the time and since X99 is supporting XEONS as well, i decided to keep it for money reasons :) I could also keep non-ECC memory, so that was a plus.