Edit: Found it, but does anybody know what document it came from?
Not the original Boeing document, but this 4-page article has some info on the concepts.Boeing Space FreighterScott Lowther, Aerospace Projects Review (APR)Horizons Newsletter Vol 37 issue 1, July/August 2011, Pages 36-39http://www.aiaahouston.org/Horizons/Newsletter_2011_08.pdf
This blog https://spaceflighthistory.blogspot.com/2016/12/energy-from-space-department-of.html has some more paintings of this specific proposal, and some basic info on the SPS program. Note the BFR Chomper-style door in one of them too
Doubt those tiny solar panels could supply power to the entire station, would take quite a lot of energy to keep the air fresh and heated.