First off, don't ask me to make one of these unless your really prepared to make it worth my while or I owe you a favor or two.
This isn't really that hard to do, but if you need a product like this it might be hard for you. Catch 22, go figure. Anywho, the concept I had was an ecu that was super easy to wire a MSS to (or any other switcher type box) as it seemed some people have problems wiring them up. I figure anyone can wire up a stereo, so screw terminals on top of the ecu was what I came up with. Obviously you could make it much fancier and just do a harness out the back end, but this is just proof of concept. Hence only the tach (RPM) output, it would be really easy to add TPS or whatever. I tied into pin 2 for the RPM output (tach) as that seems to be popular. The GND btw is the same ground the tach is referenced to, I forget which pin. I believe the MSS gives you two ground wires, one for the electronics and one for the solenoinds. Tie the electronics ground to the tach GND, tie the solenoids to any chasis ground.
Some pictures...
The ecu:
The internal wiring:
Oh, the screw terminal block I used is digikey pn WM5728-ND, $2.07 in small quantities. Its hard to see in the pic but these are made to mount on a panel and connect the screw to the other side. They're a bit deep, so your restricted to mounting about where I put mine, otherwise your going to hit something. You can get them in longer lengths of course to feed more signals out.
Enjoy!