ASRock has put out some more recent "mining" targeted boards, but I don't pay much attention to them as I don't build riser rigs and couldn't care less how many PCI-E 1x slots a board has.
Just a curiosity: by "I don't build riser rigs" do you mean you only connect gpus to full pci-e x16 (at least electrycally) slots?
So do you only get 2-3 gpus per rig / motherboard?
Yes, 3 GPUs per rig - 2 full length cards, and some sort of "short" card to let the middle card have at least ONE fan mostly clear to get some cooling to it, using the *physical* 16-bit PCI-E slots (which are usually 1 x 16, 1 x 8, and 1 x 4 electrically on most lower-cost motherboards but sometimes are 16/4/4 and often time that 16 electrically slot has to share PCI-E lanes with the second slot making the board 8/8/4 electrically in practice).
The actual price difference between a pair of 3 card rigs and a 6-card riser rig ends up not being a lot - no cost of risers, can get away with 2 PS that are a lot lower wattage and *usually* ends up being the same to a hair less then the 1 big PS for a 6-card rig (or you end up using a 2 PS setup with the same PS I'd be using) - and in some cases you have to get "creative" to get enough power connectors to POWER the risers, which adds some cost.
Keep in mind that for MOST mining rigs the majority of the cost is the GPUs themselves.
I do concede that a 6-card rig WILL usually cost a little less than a pair of 3 card rigs - but it's not all that big of a difference as a percentage, especially for those of us running NVidia rigs (or folks paying the recent GOUGE pricing on RX-series AMD cards), and I find the non-riser rigs tend to be more reliable.
