@n3rding You can also use some plastic pieces that can take air and channel it through the heatsink and then out the back in an S configuration, it requires a little more static pressure but should be a cheaper alternative while reusing the heatsink.
All you need is a little chip that will negotiate via USB-C that can be very cheaply integrated into the module and run off 12V as the entire case would.
As for thunderbolt stuff being expensive sure but it is an alternative you also have USB but in general you’d be looking at hot swappable slots that simply would take the usb-c/thunderbolt from the board and route to the back where it would then allow an expansion module to be slotted in that can be an affordable usb module or a more expensive thunderbolt module that would allow the pcie devices, now as with everything it gets cheaper with industries of scale so the problem is just taking the plane off once it’s up in the air it’s easy flying 
Case can have an IPMI that can also communicate with one of the USB-C ports allowing physical kvm and the IPMI can also be a module that takes something like a raspberry pi or a custom module that adds the video encode h265 plus audio keyboard and mouse allowing many other uses not just IPMI which would increase the interest on such a module.
Granted that you can go with a bigger server but it also creates other problems, it’s not a comparable solution here you’re looking at a highly customisable machine that you don’t need to turn off to upgrade a lot of things and that has many individual physical machines that can be rented to customers as bare metal and not virtual machines, and don’t forget redundancy and the ability to communicate with each other via thunderbolt as well that’s a 40gbps connection which would be very useful for failover/hypervisors.
As for 10G networking being bulky along with thunderbolt in general well it’s lack of engineering you can make everything fit in a lot less space thus why my module idea you can design these modules to be able to take single slot pcie cards and have the hardware and airflow it needs all inside the module making it a lot more manageable and practical but also 2.5G being able to run off USB makes it a lot cheaper and useful to some people that might even prefer 4x 2.5G vs 1x 10G etc
What I like the most is the idea of creating such a modular system that would for instance allow a small home user to run one of those system boards out of a little case you can put on your desk or somewhere out of the way or have a massive 4U chassis with several of those, the whole point is this ability that you can take something and put it somewhere else with very little effort just like you can with gpus and hot swappable hard drives that you can take from one server and put that into another from a similar brand but in this case an entire system, doesn’t have to be expensive or over-engineered just has to do the job and earn it’s worth.
I feel framework could work on such a system but there will be more of a market for something like this in the future vs today and there will be many more spare boards in the future vs today, also think framework will label their board sizes/designs with generation in mind after a few years they will likely have to change their design and layout to accommodate newer technology thus the current laptop chassis.
Everything I talked about is just ideas and a look at how a future could look like in terms of reusing parts and recycling things but also making everything easier to put together and highly scalable/customisable and hopefully open standards that other companies can also adopt, you know when you have something around like rack rails for an HP server and you’re ordering rack rails for a dell… sucks right 
