how to find a z620 v2 or later mainboard on ebay and elsewhere

Tinkering with the idea of perhaps getting myself a new(er) mainboard as a replacement in order to run V2 or later E5 Xeon's.

But what should I look for ? What serial numbers or parts numbers ? 

I do not see myself desoldering the bios chip in a workshop in the netherlands.

Thanks in advance,

Anthony