sorry to pour cold water, but it's not gonna work & fail, you will see why, build a prototype & show us with actual pix.
cost will NOT be lower, i can assure you that in fact HIGHER ! - post your prices . . .
packing & shipping+handling will be a headache hence more added cost due to dimension over weight.
philipma's setup is very ghetto, yes it works but sorry to be blunt/rude, but its a mess & a fire hazard imho.
NOT all mobos are able to provide that amount of power via the pcie lanes for a 24/7 operations, that's why a powered riser is there for a reason & to enhance cooling.
yes philipma again yeah ? ask him about his settings, way underpowered undervolted so probably that's the reason why it's working out for him but it does not apply to everyone else.
sorry guys for the criticism but just a very blunt & direct honest opinion.
it's a thumbs down for me atm until OP builds an actual product & showcase it with the points he pointed out... GL on your adventure mate, THUMBS up ! for the idea/innovation though.
http://imgur.com/a/w0jO7please note that the one that is made is actually a 6 stack however we will be converting and selling the 5 stack
stick 4 RX series gpu on the mobo, yes u definitely need a bracket, however i'd say they will be "too close for comfort". the fans will be literally sticking to each others backplate except for the 1st gpu.
the gpu that you are using is a little "thin" what gpu is that ? - most use RX series gpu
even single mining it'll be too hot imo & will still require some sort of extra cooling - extra fans = extra power consumption & costs for extra fans
it's not commercially viable if 1 is not fully utilizing what a gpu/mining software can do & to maximize profits - not fully utilized = less profit/longer roi
only 4 gpus available & only on certain mobos with 4 full pcie lanes - i hope those mobos will be cheaper than a biostar tb85
i'm sure many of us are aware that how much power the RX series pulls from the pcie lanes, with 4 on the mobo it's gonna be quite a bit even single mining with the hot air blowing onto the mobo = accumulated heat = potential fire hazard = higher chance of failure
again, sorry to have many -ve points, but if there's no constructive criticism (i hope you take it this way) there won't be any improvements.
thumbs UP for the real & actual product ! + looks clean even using non full modular atx psu. but imo, it does not really help much with the points above. i hope you take it the +ve way & come out with an improved solution/version. i do like the simple design but needs to more effective/flexible. shipping will still be a PITA, not many couriers are willing to ship certain sizes/dimensions, do double check on that & also shipping prices.
*although power consumption is low, it is never a good idea to plug 4 psu's into 1 extension cord on a single power point*