Its exceedingly likely if not confirmed that "power" armour, i.e. an exoskeletal suit can be reproduced in the Imperium.
It becomes a question of how good it is compared to the most recognisable stuff, i.e. marine armour, some instances it seems to be merely carapace armour with some artifical musculature/support.
Bounty hunters, Rogue traders, Inquisitors, Ministorum agents have all been seen equipped with power armour, and when it comes down to it, termy armour is just a more powerful version, with extra doodads.
Hell, they've even customised marine armour to fit a normal human Inquisitor, which IMO would take some doing, and Inquisitors have been equipped with termy armour, sometimes even customised termy suits for years.
Most space marine first companies (the ones using the Terminator armour) can get some pretty hefty casualties, and that baiscally means destroying the armour in the process. Even allowing for some salvage, they'd have to have new suits built or they'd never be able to maintain their First companies in termy armour at all.
You don't neccessarily have to destroy termy armour to kill the occupant, not even close in some instances.
I probably helps that they have teleport homers built in, as long as the armour hasn't been annihilated, or completely torn asunder, the part with the homer in it can be retrieved, and indeed this has been shown in at least one comic, dead marines retrieved along with their equipment.
But yeah, you need to build new armour, and if you can custom build from scratch a set of artificer armour, you can damn well build a bulkier terminator suit.
Are these the same thing as the Knights that the Imperium used to field back in Rogue Trader days that were kind of like mini Titans? Or were they more like Dreadnoughts for the living?
Knights are more like battlemech/stomper size.
