Could Blackout be Lockdown's ship? I was just thinking this because Blackout's alt-mode design Looks very similar to it. 

 

Similar, but not identical. Hence, the answer would be 'no.'

 

I have not seen Blackout's alt mode. pics?

 

Here ya go.

 

Blackout's altmode

Although comparing his robot mode from the first line art we saw of him to the line art that's on the scale sheet that showed up a little while ago. I'd say he gets an earth mode eventually.

edit: If that Voyager Blackout toy does happen, I hope it's of his cybertronian mode, but it'd probably be his earth mode.

edit2: Looks like he's simmilar to Lugnut.
In that he robot mode likely only forms from the front half of his vehicle, and his tail forms some sort of weapon.

 

No...Blackout is huge...but not that huge

 

That would be like Blackout been an Omega

 

Going with no, can`t imagine that Locdown wouldn`t know or if he did, he wouldn`t have used him by now.

 

No Lockdown's ship looks quite different to Blackouts alt mode and Blackout isnt big enough to be Lockdown's ship.

 

I would say no.
Something I did notice awhile ago was that Lockdown's ship actually looks somewhat like Sixshot's gun-mode, only with some wing/panles attached.