Just FYI... The Q35 already had accelerated plasma shots. It uses a different projectile object than the basic plasma rifle that has a faster innate projectile speed.
Also... http://img21.imageshack.us/img21/8524/multiplasbarrelchoke.jpg
Proposing the Axial Alignment Apparatus: basically a barrel choke for the Multiplas.
What other mods? How exactly does the RCW Recycler work? Maybe something like that can reduce the amount of ammo consumed per shot for the Multiplas. The visual for that could be something involving a new MF cell inlet.
I don't think it really needs a magazine expander, as it already has more shots in a mag than any of the Guns shotguns, short of the riot shottie. The mag size would be expanded by the above weapmod anyway.
Maybe a RoF booster? I could try to splice more of the Multiplas's trigger wiring in the stockframe into the Plasma Rifle mesh.
EDIT: It seems that the RCW Recycler effect works by making one out of every X shots not use any ammo. I was hoping for a flat "take off the top" effect.

Heh - nice work on the Multiplas choke. I've already fitted the Magnetic Accelerator to the Multiplas in a slightly different way, but I like the idea of widening the 'muzzle' a bit (though I don't think I'll have it 'trumpet' out like that). At this point I'm planning to have the Mag. Accel. and Dual-Cell Harness on the Multiplas for the sake of consistency; it
looks like it should support them. It also means those two weapon mods can be used across three weapons.
The third weapon mod for the Multiplas though... at the moment I've still got 'Plasma Rifle Limiter Chip Bypass - Increases rate of fire' in the list, but I
would like to improve on that. I'll give it some thought; thanks for the suggestions.
Oh - still on the Multiplas; I just noticed that one of the hoses on the left side is mis-aligned. Something we should both fix on our versions, I guess.

And thanks for the heads-up on the Q35 projectile; I didn't think to check that. It fits with what Obsidian did with many of the unique weapons though, having them basically pre-modded with the same or similar effects to a modded version of their common counterpart.
I've been debating what to do about that (now I'm talking to everyone, for the record; not just MadCat). At this stage my thinking is that WMX will remove the 'integrated' mods from the relevant unique weapons - and they can be added using the same weapon mods as their common counterparts. Basically as the list in the OP has indicated. How I intend to balance this (in fact how I've
already done it for a couple of them) is that the stats of a given unique weapon will be the same as - or slightly nerfed when compared to - what they are in vanilla (but only to maintain consistency and believability). However, once fully modded, they will be more powerful than they are in vanilla.
This gives a concrete benefit to modifying them, and also adds the gameplay involved in seeking out mods for them and then modifying them (which is a large part of the appeal for me).
I'd be interested in knowing what people think about this approach.

Edit: Well how about that. http://www.engravingglossary.com/images/Renaissance%20Browning%20.jpg looks somewhat http://i21.photobucket.com/albums/b300/jlollback/falloutnv/maria01.jpg, wouldn't you say?