Crazy idea: Have you ever thought of porting your desktop environment to Genode? ( https://genode.org/ ) And fully integrating their Sculpt into it? I mean, on Amd64 you are already binary incompatible, so that wouldn't count as an argument against it.
Someone suggested it (but then, the community is large enough that all far-fetched-but-not-impossible ideas have probably been mentioned at one point or another :)).
I don't really know what the differences between porting Haiku's userland to that or to Linux would be. Everyone loves to make arguments about how microkernels are so great and all, but there still isn't a major operating system or distribution with a significant number of everyday users on one. Plus, all of our same philosophical objections to using the Linux (or any other kernel) as the basis for Haiku would still apply.
Hm. For one they have seamless Virtual Box integration. Which means NATIVE vbox-port running on that, and fast. Can use one of the fastest (message passing) micro kernels available. Which seems fitting to the concepts of Haiku from my layman point of view? What i'd imagine is your desktop, with the exact look and feel and usage concepts ripped free from Beos/Haiku kernel stuff, and running atop SeL4 instead,
with BFS running in some user task, thereby not loosing all the database/tag-capable stuff for the DE.
Maybe even having more drivers for contemporary hardware?
Also security, network stack?
