Hot Toys 1/6 Iron Man versions?
 

I've been on a bit of a HT kick over the last few months, and I'm trying to build up the "hall of armour" from Iron Man 2. I have the Mk II and V suits, as well as outstanding orders for the hall units and the MK I, IV and VII suits.

I've not been able to find any evidence of MK III or VI suits, though. Do these items actually exist, and if so, where am I likely to find them still available?

yes every single armor has been made.
E bay is the best place I'd say
or your local comic book store or try searching for hot toys on google might find some online stores near you

You can still buy the Mark IV from sideshow collectibles, unfortunately you need to buy it with the suit up gantry which is near $500 at that point. So definitely eBay or comic book store st this point unless Hot Toys decides to redistribute with an update like they just did with the Mark I & II.

As for the Mark III, that is so old now I've actually heard from people who own it that the paint job has faded into a pinkish color. So I really hope that gets an update. So far I only have the Mark VI and have the Mark VII on pre-order and am halfway through payments on Iron Monger, so it'll be a while before my hall of armor is completed.

there are two versions of the MK III out there. the normal, which is mostly unpainted colored plastic and HT first attempt at the IM license and battle damaged version, which is essentially the "premium version" with a updated sculpt accessories and fully painted. they go for a pretty large amount of money since they where all limited runs, now that they are done being manufactured they cost reflects that.

imo if you are not a total completionist do not even bother with the MK III at this point and cross you fingers they repaint the MK I AU as a 2.0 MK III.

the VI may be a little easier to find as it also has been re-released twice now. once for the IM2 movie and a second for the avengers. both are the same figure but with different paint effects and accessories. the original IM 2 version comes with a full set of battle damaged parts which you are able to swap on and off the figure and includes a base. you will have to go for a secondary market for it since it is also not manufactured anymore and again where all limited runs. the suit being one of the more popular ones has also drives the cost up...

you should try sideshows forums (mod remove this is if considered advertising) where collectors often put up HT IM for sale or trade at non ebay rape prices.

I have a battle damaged mark 3 I may sell if the price is right.

These are the primary focus of my current collection--here's what I believe is a fairly exhaustive list.

Mark I
Mark I (v2)
Mark II
Mark II (armor unleashed)
Mark III
Mark III (battle damage)
Mark III (gunmetal grey)
Mark IV
Mark IV (secret project)
Mark IV (w/ gantry)
Mark V
Mark VI
Mark VII [March/April 2013]
War Machine
War Machine (special version)
Iron Monger

The only ones I don't have are the non-armor figures (stark, widow, whiplash), the gantry, and the yet-to-be-released Mark VII. There may have also been another re-release of the Mark IV in there somewhere.

The only guidance I can offer around collecting these is to lock in your preorder as early as possible with your favorite vendor.