Sorry to say but I'm going a bit bigger than you'd probably like. When you said 66"-68" I thought you meant WMS to WMS. I'll be running 99-04 superduty axles (I just measured the WMS to WMS to be 69.5" front and 68.5" rear, stock IFS width is 60.75" WMS to WMS), 39 or 40 inch tires with 4.5" BS wheels, the overall track width will be ~83" (stock is 66.5"). 3-link front with 2.5x14 coilovers, double triangulated 4-link rear with 2.5x8 coilovers and outboard cantilever suspension to produce 14" of travel without cutting into the cab. Trying to get it as low as possible, as much uptravel as possible, no compromises kind of design. Obviously this design is very particular to my desires, but nobody made or sold what I wanted so I decided to design my own.
It's been a ton of work so far and there's a lot of details left (nevermind the actual build!), but things are starting to come together. Here are a few screenshots: