The chemist over there who seems to be taking a lot of personal interest into this found this article.
http://www.lubrizol.com/press-room/m...onProc2-08.pdf
As of now, sounds like he's leaning towards the build-up being related to specific stations fuel additive packages. Meaning nothing to do with injector brand, type of fuel line, filter, etc. Different companies use different additive packages. So depending on the mix your station uses, may directly effect how much of this build-up you may see.
Just a theory so far, but seems to have some factual basis behind it.
If this really is the cause, apparently the Holiday in Blaine has a decent mix as I've yet to see this issue on my car
