What I've done is create beefed-up textures (1024x1024 resolution) for both of these weapons. And no, I didn't just scale up the original 512x512 resolution textures and sharpen the image, because that looked horrible. For the "Q-35 Matter Modulator," I took the 1024x1024 texture of the ordinary Plasma Rifle and edited, recolored, and redesigned the texture to be equivalent to the original Q-35 texture. Thus, we end up with a much sharper looking 1st person appearance for the Q-35. I did a similar trick for the Tesla-Beaton, using the normal Tesla Cannon 1024x1024 texture, but had to go one step further for the "Rusted appearance." The rust isn't something that translated well, despite most of my attempts. To replicate the apearance of the original on this larger texture, I had to hand paint the rust on, using a sponge-styled brush in photoshop. Seriously, of all the textures Obsidian could have forgotten to include, why did it have to be the one with rust? On an interesting note though, the default Tesla Cannon textures include the wire-style rails of the Tesla-Beaton in it's sheet, even in the right color, so that part was easy.
In addition, I made Completely new textures for three weapons from Old World Blues. These three weapons were unique, but didn't have a unique appearance. These three were "Elijah's Advanced LAER" (which used default LAER textures), "Elijah's Jury-Rigged Tesla Cannon" (which, for whatever reason, uses the Tesla-Beaton Prototype's textures), and "Christine's COS Silencer Rifle" (whish uses the default Sniper Rifle textures). This was actually how the mod started, which edited these three weapons. I go more into detail on the Mod's page.
This is my first mod, so feel free to give me recommendations/advice/money/whatever.
Link: http://newvegas.nexusmods.com/mods/46346