you already know this article?
https://bitcointalk.org/index.php?topic=64450.0600 USD from his source, or near double - so 1200 USD directly by trentonsystems..... i think the starting invest just for a board is to high. for 100 USD each i get a 5 - 6 GPU supporting Board. so with 500 - 600 USD i will get 25 - 36 GPUS.
Just CPU and RAM you will save a little.
I have Ordered 4 of these:
https://mineshop.eu/cables/pcie-adapter-1-to-3-slots-detailstill waiting for testing if they are supported by SMOS. I have already made my Rigs with a 1700 - 2000 Watt PSU system. so it would be great if these extenders would work. Unser Windows they are already running. but still dont know about linux support.
Yes very familiar with that Topic on trenton system.
BTW whats the theoretical limit on how many Gpu can you support for mining with the 1 to 3 pcie adapter i wonder if that would or could work.
Let me now your experience in details.