Create a differential Op Amp Subtractor With Single Supply?
For sure it's possible!

Check here:
http://www.ti.com/lit/an/sloa030a/sloa030a.pdf
Page 11. Case 2 

Vout = m*Vin - b. This means m, some gain and b some offset. 

You can ignore the cap and rl for interpretation purposes. 

I highly suggest reading that whole document since it has a lot of knowledge.

Cheers!