I have provided the engineering and construction for many projects in this fashion.
For instance, a large clean room, class 10, in Marina Del Rey Calif, for Granger Associates. Their estimates were in excess of 2 million dollars.
Complete costs on this project were under 500,000 dollars. 20 zones, air shower and locks. Raised floor, spectacular see through floor to ceiling plexiglass wall construction.
.... and many refrigeration projects along the same lines.
Some of the surplus was new in the crates, others never used but stored outside...$200 for a 150 ton York reciprocating compressor for example. That and other measures saved that client over 50,000 dollars,
These projects can warrantied and bonded to meet any requirement.