This large HP Z840 has been my daily driver for heavy duty simulation jobs.
Dual Xeon E5-2697A v4 (32 physical cores) - probably the fastest CPU of its generation
Vapor coolers
32GB registered memory
512GB SSD
DVD
4 3.5 HDD bays w/caddies
Huge 1275W power supply
Quadro K2200 GPU
It's in pretty good cosmetic condition, with some scratches on the case but no real damage. Everything works. It's very heavy, and therefore prohibitive to ship, so don't bother asking.
Questions welcome. Cash is king. Thanks for looking!