Errr...okay. Lots of opinions floating around in here. If blowers were no good for diesels, then what have companies started to produce them to fill the power void where the turbo falls short?
Your EGTs do not work the same on a gasser as they do on a diesel. If you cram too much air into a gasser, you burn stuff. On a diesel, the more air you cram in, the cooler the EGTs are (this is leaving out the ACT from boost/IC debate). I think what the debate was about 1100* is a good way to see that when you are out of fuel, it will not heat up anymore. Not sure if that is 100% what he has done, but I think it is one way to make it work.
Now for the blower setup. I am going to run a M90 off of a supercoupe. The output of the IDI is only 20cfms more than the 3.8. With a stock seutp, they made 15ish psi. I think with mine, I will be able to see 10 if not more. If you have never driven a positive displacement blower vehicle, you should before saying they will not work. Instant boost is king. And when you are doing things like I am, you want to operate as low in the RPM band as possible.
SWS
You are comparing an eaton m-90 to a detroit 8-71. The eaton superchargers are made to make a lot over atmospheric pressure boost, the detroit blowers were not. The eaton superchargers can turn 12,000 rpm continually, whereas the detroits have to be modified to spin with a gasser (not sure of the rpm). There is a reason all the manufacturers use eaton blowers instead of 8-71 blowers. Sure 8-71's look cool, but I just don't think that is the best choice. Why do you think Detroit went to using turbochargers? Also, the m90's are easier to run an intercooler, and if you bolt an 8-71 to go straight into your intake, you can't cool the air.
If psi and cfm are all you care about, than just about anything will work, but air temperature is just as important as those two. The number on your boost gauge doesn't mean everything.
If your 6.9 at 70 degrees n/a (14.7psia) 3300rpm will flow 25lbs/min, than with 15psi boost (29.7psia) non i/c at 300degrees the same engine will flow 50lbs/min right? Wrong. It will only flow 35lbs/min. If you get that temp down to 130 degrees ( typical intercooled temperature) you'll be at 46 lbs/min. All these would be at about the same cfm, just more actual air.
I'm not saying nobody should put on an 8-71 blower it would be cool, and it would work okay, but I don't think it would be any better than the turbos that are already widely available. Now, if you absolutely need the boost right off the line, that's a different story, but the turbo truck will be better off right when it spools.
I still think the best think for about 20psi the best thing would be an m112 blower pushing into the ats or banks turbo, then off to the intercooler. Then, the supercharger would only have to make 8psi boost, which would keep it efficient, with a low power draw, and have really good top end. You would probably have to up size your turbine though.