I mean from what we know, all the NA datacenters seem to be housed in the same location if not the same server room. So at the very least it should be possible to do cross-datacenter play between datacenters that are housed in the same location some day. It's just a matter of figuring how it'd work and getting the funding to do it. As SE themselves is a bit... Well... Let's just say Yoshi-P had to beg for the funding for the last round of upgrades.