Look at Xeon E3, for example:
https://www.newegg.com/Product/Product.aspx?Item=N82E1681911...
The 80W TDP worries me about though, cooling, noise and money/pollution wise (the extra 45W make around 400kWh/year).
Considering the CPU will be idle most of the time, do you have figures about the actual idle consumption of an E3 based machine?