I've done something similar to what you guys are talking about. I too really liked the Griggs but the price is a little out of what I wanted to spend. I am putting in a 4.6 4V motor too so I needed to get rid of the towers. I am not crazy about the mustang II setup for what I was wanting. I am using the SN-95 spindle, fox rack, and a custom crossmember and towers. Really, you can make any track width you want. I set mine up a little wide since I am running FR500 wheels made for the SN95. The fox track width is almost exactly the same as the 67-70, but the fox spindles are not as nice. You can use '94-95 spindles which are the same track as the fox, but use the same brakes as the 96-04. If you are doing your own deal, you really need to pay attention to your geometry. I looked at a stock K-member
suspension points for the lower and modified from there. I moved the lowers a little and designed a shock tower, upper a-arm, and a-arm adapter. I tried to use a standard round track style a-arm but ended up making the ones on the attachment.
The rack is moved a little bit from the stock sn-95 geometry. Personally, I would not go to strut design like the stock sn95. In my opinion, a strut design would be a step back from a modified stock sla setup.