With the RB25DE and it's cam angle sensor running the Wolf V500, I was able to run sequential injection. Wolf make a universal trigger disc for various engines/cylinders so when you buy it ($49), you have to remove some teeth that are not used. Steve Newing knows by heart which ones are needed for a L6 so he would be the best person to ask. One good idea would be to adapt a RB series cam angle sensor on the front of the L series rocker cover eliminating the crank pulley sensor. Bit of work which I might look into. You also need to hall effect sensors; $85 each.
The only advantage to sequential is fuel economy when putting around on light throttle. My previous Wolf was setup to batch fire two injectors per cycle so one cylinder was getting fuel for nothing. I have noticed the fuel economy with my RB setup is very good, on 3/4 of a tank of fuel, I can drive to Sandown, race for the day and drive back home with some fuel to spare. Then again the cams are standard so it doesnt drink heaps but I still think that's good!