It may be a while, but you just know something along these lines are going to happen sooner or later. Xenos fortifications would have an immediate niche an people would love them. With the merging of Forgeworld and GW, something along these lines becomes even more of a possibility.
Please remember that this is a rumor.
via an anonymous source on Faeit 212
"It is possible that we're going to see a new Fortification exclusively in Necron armies (including FW Harvest army).
The Fortification would be a Necron-Style Aegis Defense line, restricted to the Silent Armies of the Necrons."