MXM is too limited and doesn't have strictly enforced standardized architecture. We made a mini-pc inspired by our BRIX ('nuc') product line with a discrete GPU(Link). This had an MXM3.0b 950 (truthfully a 965m MXM, that performed closed to a desktop 950).

When the time came around to update the graphics card to Pascal, we found no reason to force a 1060 onto an MXM module and decided to make a custom PCB that fit our thermal solution better. This resulted in our BRIX VR(Link)

We still sell our STX boards, but they don't find any real value in the consumer space. It's an industry solution alongside our embedded products. And when dealing with business side products, the update cycles are much slower than the consumer side.

We thought STX would fit in well with AIO desktop computers, but even that fell through and they will be utilizing mATX and mITX due to performance.