Thats what i was thinking except to go that route i am looking at least $200 more in supplies. I am curious if I will make that back with the little gain in efficiency?
It is true that a PDU costs more than a duplex outlet but you will be able to reuse them as you grow. I am not sure you got 200 dollars.
http://www.ebay.com/itm/30-56051-01-Compaq-220-240V-Single-Phase-PDU-Power-Distribution-Unit-24Amps-/390707938184?pt=US_Power_Distribution_Units&hash=item5af8020388 are 50 bucks each,
http://www.ebay.com/itm/Lot-of-3-HP-E7674-63001-100-240V-50-60Hz-16A-Power-Distribution-Unit-PDU-/251276014756?pt=US_Power_Distribution_Units&hash=item3a8137b4a4 are 75 for the three. Not sure if they are any good but that's what ebay found.
How far from your panel are you going to put your miners? How many slots do you have in your panel?
I would make a little spreadsheet comparing 6 x 120v20a, 3 x 240v20a and 2x240v30a.
The 6 x 120v20a circuits would require 6 runs of 12awg wire, 6 single pole breakers or 3 of the 2 in 1s, 6 duplex boxes and 6 duplex outlets. No power strips needed.
The 3 x 240v20a circuits would require 3 runs of 12awg wire, 3 double pole breakers, 3 duplex boxes, 3 outlets and 3 16A PDUs
The 2 x 240v30a circuits would require 2 runs of 10awg wire, 2 double pole breakers, 2 duplex boxes, 2 outlets and 2 24A PDUs
Of course, a more important question is how long you plan on keeping this up and do you ever expect your power consumption to go DOWN. History shows it rarely does