Of course. I don't know why I didn't consider Garth's maxband, since it's one of the best things about the whole Necro spec (not to say there aren't others-- as I've said elsewhere, Necro is generally one of my favorite specs, maybe my single favorite). I did think about Iron Man, but I actually am inclined to think that Finesse is a better tech 1 complement to Necro/Disease than Bashing is. Iron man makes good trades, to be sure, but while Necro/Disease lacks a 3/4 for 3, it's already got 3 different options for a 3/3 for 2, and Plague Spitter is a 3-cost tech 1 that trades well with bigger things, though I think it's definitely a more defensive option than a 3/4. When it comes to trading well on offense, Bone Collector gives fantastic value for 2 gold. Bashing tech 1 feels a bit like more of the same, whereas haste adds an entirely new dimension to the codex. Now that you mention Garth's maxband, though, I do see the value of Bashing tech II with Necro, though I must say that I think Grounded Guide is a spectacular Garth Maxband grab (skeletons love global buffs, and the Virtuoso synergy is tremendous if you went with fencers in tech 1).
In general, I think Disease probably synergizes better with Finesse than with Bashing, due mostly to River's spells (Discord + Orpal maxband seems really strong, especially if you throw an Abomination or a Plague Lab into the mix, and Two Step looks really pretty on Plague Spitters and Abominations), but also partly due to Tech I haste and Blademaster (a minor concern, I admit, but the only thing that combos better with swift strike than damage as -1/-1s is Deathtouch, and Disease has 3 things with one or the other, two of which don't require a Tech Lab). That being said, you're probably right that [Bashing]/Disease/Necro is stronger than [Finesse]/Disease/Necro, because the Necro/Bashing synergy is probably a bit stronger than the Finesse/Disease synergy. [Finesse]/Demon/Disease seems like it's probably the strongest option for a black/neutral combo including Disease, though.
@Raiddinn, I have to disagree about picking Bashing over Finesse with Demon/Necro. Bashing and Necro may synergize well, but Finesse and Demonology synergize amazingly well (Harmony/Dark Pact, Discord/Terras Q or Twilight Baron, Two Step+basically any 2 Demonology units, etc.). I don't think I'm going out on a limb here, since [Demon]/Necro/Finesse is considered top-tier (which I imagine is why you mentioned your preference for Bashing), but I'll go one step further: if I were going to play around with that codex, I'd be more likely to swap out Necro than I would Finesse. Even if I wanted to keep it mono-colored, I think I prefer [Finesse]/Demon/Disease or [Demon]/Finesse/Disease or even [Finesse]/Demon/Bashing (in that order) over either [Bashing]/Demon/Necro or [Demon]/Necro/Bashing. The one caveat I will give to all of this is that Troq is a somewhat better target for Metamorphosis than River, but River is still fine, and a better hero in general, so the difference isn't worth what you give up.
Edit: apologies for the wall of text. I can get a little long winded sometimes, even (especially?) when I don't entirely know what I'm talking about, which is admittedly the case here.