To cover the power supply, which is still needed after the above linked charger is bought; a very good reliable 12v 41a 492w power supply can be had for less than $15... you can up that to a 24v 41a 984w for about $20. An iCharger 206B is capable of 20 amps and is available for $120ish. An iCharger 3010B is capable of 30 amps and is available for $180ish.
So, to recap:
Power supply and above linked charger: $300
Power supply and a 206: $140-150
Power supply and two 206's: $260-280
Power supply and a 3010: $200
Power supply and two 3010's: $380
The reason most high powered chargers do not include a power supply: cost.
Purpose built power supplies that provide what these chargers need are expensive... $300+. The only reason we can get supplies for cheaper is due to our creativity and the ability to use retired server power supplies, which can be bought for fractions of pennies on the dollar compared to what they cost to build new.
Whatever it is I just said... I could be wrong.
Just an update. I was able to return the Onyx charger that I bought and I ordered a Hyperion DUO charger and a 24V, 1000W power supply. I think I will be very happy with the setup. Pics after I get everything delivered.
Thank you to all for the suggestions, ideas, and opinions
I know they're having their break there by your brake drums. No, you're not invited.