I would use a Baneblade chassis as control vehicle and two other Baneblade chassis as base for the superstructure which holds the gun.

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I converted my Brunhilde Tractors to an armored versions.  Besides my IG don't use "Zombies" ...                                                                                            Medic Rhino for scale ...                                                                                                                                                                            

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Legion 4 "Cry Havoc, and let slip the Dogs of War !" ... "People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf."

The problem with using a baneblade chassis is that A) it's easily recogniseable as a baneblade, and B) everyone and thier dog are doing 40K baneblade conversions, and I was aiming to avoid doing the same with my project.

How do we feel about something stylistically similar to the termite transporter for the command car? It's probably about the right size, and although kinda boring, it is canon. (Epicollector link)

An alternative might be to base the entire thing on a huge tracked chassis, similar to the mole or hellbore transporters (Another epicollector link)

it's not very pretty, but it is the largest modern tracked vehicle I can think of, so the Crawler used to transport the space shuttle might give some ideas:

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-Vaaish

Well i actuall ymeant the size not the chassis itself.  

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I think was was shown in a similar thread a while back, now as then i believe it to be   stick a cathedral made of steel girders on top of it, a death ray out the top of that and a SHT on the front ...and somehow do it in a way that doesn't look like the current/old design 

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Bigest tracked vehicle?
Voilá!
http://en.wikipedia.org/wiki/Bucket-wheel_excavator

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Ahhh, ok. Sorry for misunderstanding you.    Something around baneblade size is probably about right for the carriages, altohugh maybe they ought to be a bit wider.

The shuttle transporter with a pair of huge guns on top is pretty much what springs to my mind when I think of an Ordinatus, although I like the tracked-carriage version as well.

Don't be silly BL, that's clearly a Khornate daemon engine not an ordinatus

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The Space Shuttle Crawler would have the right size for an Ordinatus Minoris.

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Ah BlackLegion, it warms my heart to see pictures of a vehicle that probably needed as many Civil Engineers as it did Mechacical Engineers to design it.

I forgot about that monster. Looks like something orky though

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-Vaaish

The shuttle transporter in 6mm would be about 140mm (just shy of 6 inches) - perhaps a little too large?

We aren't talking 1:1 conversion to 6mm. Think of it more as design inspiration to concept out something different that still feels functional.

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-Vaaish

Judging by the description of the Ordinatus Marsin "Dark Apostle" even 14cm would be to small.
Something the size between a Warlord Titan and an Imperator Titan would be more appropiate.

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