This was from a few days ago, but I am sure that there are people in the community that might be looking at picking up a few of these kits in the near future. So have no fear, MK VI armour and most likely additional kits are being worked on for re-releasing as soon as they are done.
If you want to know more about the different power armours of the Space Marines, 40k wiki is a great place to go by simply following the link. http://warhammer40k.wikia.com/wiki/Power_Armour
via Wulox on Bolter and Chainsword
http://www.bolterandchainsword.com/topic/318149-no-longer-available-armor-marks/?p=4275484
I had been intending on ordering some MK VI armor from FW, not knowing they were now "No Longer Available". I knew the none-legion variants of the other armor MKs were no longer available but I assumed that was because they had a legion variant.
Anyway, I emailed Forgeworld inquiring as to why the MK VI was now No Longer Available, and I received this reply within less than an hour:
Hi There,
Thanks for the email, fear not for the kits your after have been temporarily removed for remastering. We have decided to make a few improvements to a few of our kits and will be working on a good number weapon packs and Heresy era armour kits to bring them a little more up to date and allow for a more enjoyable hobby experience.
Please keep and eye on the newsletters and keep coming back to our web store as once the work has been finished they will go back on sale. For now we don't know how long these projects will take but as we understand it they will be done in batches of products
Thanks again and speak soon.
I can only assume those armor marks that are no labelled "No Longer Available" are being redone to accommodate the new bolter+hand setup.
As said previously, if this has been covered elsewhere lock the topic, just wanted to inform people that likewise wanted to order the armor marks that are no longer available!