well...not 100% sure, but the 2215 1020kv may work on 8s. Or possibly the 1521 1577kv..although I am not sure if it is big enough for your intended application
Here is where I was looking at these motors...
http://www.offshoreelectrics.com/pro...FQk75Qod-3f7dQ
1. MBX-6 T8 1900KV, RX8 ON 4S
2. MBX-5T 1520, MMM ON 5S
3. MBX-5 ONROAD CONVERSION 1515, MMM ON 5S
4. MRX-3 ON ROAD CONVERSION 1512, MMM ON 6S
5. TEN T 2650 T8, MMP ON 3S