After reading the 'fun' over the new Age of Sigmar rules and then seeing the new 40K rules (and the lessons GW took took to heart from the AoS mess ups) I got the surprise of my life when my son asked if we could get back into 40K and he would like to collect Tau again...
Now I've been using 15mm (and smaller) myself and do not have the room now for a full 28mm+ army or two (esp. as we are moving to a smaller house) so I was a bit stuck till I stumbled upon Shadow War as the new release (missed the original boxed set) and talking with the GW folk I found it was Necromundia and set for small number of troops (OK I now know it was all over the 'net but I did not bother reading it at the time).
Purchasing the rules I saw that it was the classic 'clean' and bright colours where as my thoughts are more dark and grim matching the Underhive being at the bottom of the tower and grot always falls downward

so I knew the normal GW form did not do it for me.
Digging through the bits box I came up with some dark gravel / stone - perfect for bases but no real terrain suitable (some Dark Age / Fantasy buildings & walls etc) so I knew it was going to be along haul through eBay and local shops.
So the aim is to make a 'dark' future, full of grit / grot and bits - avoiding the outdoor style ruins and a bit dryer than Blade Runner!