The X68000 is a nice machine, a friend of mine has one and I'm still looking for one for my collection but they go quite high most of the time (well over 1000$ in Sweden and abroad you have the crazy shipping), they have a lot of PSU problems nowdays tho but it's quite trivial to fix for most of us
The IBM PC compatible PC I have never seen, would be nice to have in my collection but nothing I will hunt for, I have seen a few russian clone machines sell now and then with the "amiga" wedge look
But to buy it and replace the motherboard with a modern machine mini-ITX board would not be something I would do, it's not any form of recent standard on the innards anyways so would be the same hackjob as doing the same on any Amiga wedge and such a waste on a less common machine.
I wish for a Wedge case for a modern machine but without the connections to use CNC machines etc it's hell, so I have been thinking of experimenting with building one in pepakura and fiberglass and reinforced inside but doubt the results :/ ( will try to build a Fallout terminal before I try any wedge case to get the hang of it).