My portable system is actually a NUC, (one of the i5 kaby lake model). And I too like to choose my own portable display, keyboard, mouse, etc.
I even got a MAXOAK battery pack to make it portable/battery powered with DC/DC connection.
SO it can be a lot of fun, but for overall performance/value it isn't quite there, but it seems like you have other things you value more (cooling quality, build quality etc.) so can't fault you for that.