I will make this simple for you.
Buy a rusty frame (cheep and strong)
Use trex booms  13.00 for two.
Turagy Plush controler's because You can not pull more than about 7 amps per motor on a MK Octo before you smoke the board.
This is what i have learned over the last couple of years.

OR option 2 see below.

I sold my new Octo II fully loaded for 2,900.00
If you want it i will call the guy that bought it and still sits in a box. 

I have built quite a few XL versions using both the MK frame and the Droidworx frames. The MK Frame is a good bit lighter but not as rigid but it will carry a Canon 5D with no problem. If you feel like you want to stiffen the frame then add an extra center plate to the bottom so as to double the thickness.
The MK ESC's work just fine if you use the XL power ring with the extra capacitors. The caps help keep the power ripple down which is an esc killer.
If you want some smooooth motors at a good price I love the Avroto 2814-11S http://montorc.com/M2814Shaft.aspx with an 11 or 12 inch prop. Be sure to spend the time making sure your props are very well balanced.