Guys,
My buddy recently bought FMA powerlab 6 with parallel board i was amazed that it can charge 4 5S 4900Mah batteries @ 7.5 amps at the same time, can I try this with my Hyperion 720i charger rated 500w x2. Anyone tried this setup? There's a parallel charging board for 6s in Hobbyking selling at $10. It would be awesome if you can charge 4 or 6 5S batts at the same. Any suggestions?

You can parallel charge with any charger with the right connectors. You just need to have a power supply and power source large enough to handle your needs.