Rebel Minis have added individual 15mm HAMR Suit sprues for sale.
From their website:
I have had a bunch requests to sell some of the sprues from the HAMR suits. These are great for Kitbashing your HAMRs or other Mechs. Here are the Sprues I have up and John is working on some more as we speak.
They have also posted photos of some painted samples of their 15mm sci-fi figures in the same blog post.