Luna BKB + Ethereal Blade = Invulnerability?

If this were ever done, it'd be on Luna while she cast Eclipse. She's the only hero I can think of who would benefit from both items at the same time (except for Crystal Maiden with just Ghost Scepter). Using them at the same time would make her unable to be attacked, and counter the magic weakness from Ethereal Blade. Would this grant you invulnerability for the duration of Eclipse?
Of course, this would be with a HotD and either Manta or Butterfly.

I don't think it would necessarily be a bad idea, but it takes a lot of time to farm it and most of the time a Black King Bar is enough to survive until the Eclipse finishes unless caught 1v5. You would still be susceptible to ultimates like Fiend's Grip or Black Hole, and enemy BKBs make your Eclipse useless. But it's a nice concept on paper.

It could easily prevent you from being targeted if you did it, even if there was a Fiend's Grip or Primal Roar, etc. there wouldn't be much follow up. The only downside I see is that by the time you get all the other Items that you need, it's going to be hard to get enough damage out of the Eclipse to justify this when a Satanic already gives you a 2nd live to keep you alive.

Doesn't magic immunity disable ethereal form?

I don't think that it will grant you invulnerability for the duration of Eclipse, like Peppo mentioned there are ultimates like Fiend's Grip and Black Hole and others who go through magic immunity and ghost form.

As far as I know, BKB does not disable ethereal form. Also Rupture goes through magic immunity as well as the initial damage of Echo Slam.

Rupture isn't magic damage, its straight HP removal and cant be blocked (ignoring Linkens Sphere)

according to dota2wiki it can be used on magic immune allies, but not enemies.
Source: http://dota2.gamepedia.com/Ethereal_blade

i think, that combining BKB and E-blade seems like a nice gimmick... But as already said: its hardly worth the gold on Luna as there usually are better items (like Satanic or Butterfly) that can help you to survive physical damage.

EDIT: i have to confess, that i didnt know that Ethereal Blade can be disassembled, so maybe it could actually be a valid Mid-game item.

you know, like: Treads -> HotD -> BKB -> E-Blade -> Satanic (-> disassemble Eblade) -> Butterfly

True, and the Ghost Scepter is still relevant, especially in the Late Game.

You can just use Omniknight to do it on any single hero.