I'm skeptical that Vassal40k's closure means much about the ability to play the relevant vassal module on the vassal server -- and I don't see anything on the vassal forums suggesting that R. Kinney or the other people involved with the server and the basic engine have received a cease and desist note.

Further, it is by no means clear that the vassal40k/epic engine violates GW intellectual property, beyond the use of familiar names for units (and the K for 'the green creatures who were once called orcs').

I somehow doubt that there would be much objection to a Vassal module featuring the "Marine Corps," the "Hunter-Scavenger Mob", or the "Red Guard" to say nothing of "Eldritch Caste" etc.
 
Perhaps such a module should be posted on the vassalengine site.