Well I tested the shockwave you attached, m2258734a, and I must agree it's quite pretty.

DaBrain! [which, as you say, is one of your non-tiled versions that doesn't need a model.] The way I first got it to work was temporarily remove just the mv_effects file, then make a mod folder with this shockwave in data\effects. (even worked in data\maps which I tried first.) No trouble at all.
Upon further testing, the ONLY file necessary to remove is the mv_effects\models\shockwave.pof . The 3d maps and glowmaps then get ignored. Question to you who know more about vps and precedence... I know that putting a file in the data folder overrides the same named file in a vp. So is there a way to override a file in a vp in such a way that it isn't used any more? Like in this case, we want to tell the game to ignore JUST the shockwave.pof file. Similar concept to what we can do now with modular tables (love em). Idea! Perhaps code so that if the game finds a size 0 byte file, it ignores it and sticks with something earlier in the precedence?
Hey DaBrain, did you ever make the 'dry' dust/debris shockwave for asteroids I think you mentioned a while ago? Not trying to push you if you haven't

just wondering if I missed it.