The general pathway to MXE is known but there aren't any "recipes" out there like there is for stuff like ketamine. That said, it would only take undergraduate knowledge of organic chemistry and a bit of extra research to generalize ketamine's "recipe" to MXE.
I actually wonder what pathway the HXE source used to get there, because I believe the best route goes from MXE. From MXE, your one step away from HXE, and also from something like 3-MeO-2'-HO-PCE. Actually from any of the 2'-Oxo-ACH's you're only one step away from the corresponding 2'-HO-ACH, which makes me wonder why we haven't seen those. I'm omitting details to avoid synthesis discussion, but someone please point out if this strays too close and I'll edit.
Anyways, HXE definitely sounds intriguing. DMXE ended up being quite disappointing for me, which makes me think that the more electron density at the 3 position, the better.