Howdy.
Speaking as a relatively uneducated and ignorant Okie, I think you are seeing the difference between 65nm tech and 28nm. Look at the space requirements for the minirig, and then the monarch which fits in a double PCI-express slot. Be warned, though, that this product probably doesn't exist anywhere on planet earth ATM. I'd pay four grand for one today, but not six-eight-ten months down the road. I found the disclaimer about "If you are uncomfortable waiting until development is complete and the product is shipped, do NOT pre-order this product" humorous and a bit touchy, after all the heat BFL has probably dissapated over the last year's order to delivery rigamarole.
https://products.butterflylabs.com/homepage-new-products/600-gh-bitcoin-mining-card.htmlrussell