@Griz882 wins the contest - I learned a little after researching..
These jackets are part of the USN's Multi Climate Protective System -- consisting of a Goretex jacket and trousers; Polartec jacket and vest; Polartec stretch shirt, overalls, and pants; Polartec face mask.
HR 2638 (from September 2008) secures funding of $2.0M for 1, 172 sets of MCPS. The language states the system was developed and introduced in 2004.
MCPS is specifically mentioned in Congressional Record in 2004, 2005, and 2008. I've been unable to locate anything more recent.
So, we have a design 10+ years old and not one single example with a label containing an NSN, official nomenclature, etc. Also, many jackets for sale via military surplus stores or via Propper combined with small numbers seen in actual military use.
No doubt these were issued and used by at least some members of the USN/USMC. Just seems odd that they're so sporadically seen despite being around for a decade.
Perhaps this post also belongs on "USN Polar Ops" thread...