Who made that spec sheet? The Backup system is supposed to rely on a USB stick or something similar? If there is anything on the server you don't want to loose then RAID 5 is pretty much mandatory. There are a lot of mainboards which support it by default, so no expensive RAID controller is necessary.
You can pick up the i7 3770 for about 240 euros now, alternatively there are some xeon CPUs clocked slightly lower and usually without an iGPU for sub 200 euros. These are still using hyperthreading and are therefore more desirable than an i5 for a server.
I don't know if ECC is necessary for that server, but i don't have any personal experience with it anyways.
Most of the other requirements seem to be achievable on any system running server 2012(r2).