It seems that your experience and my experience are vastly different when it comes to the MS. I've had zero noise issues in my MS2 equipped vehicles, and MS3, though I've only briefly run the MS3, just because I haven't had time to get it all set up. The same goes for the MS3Pro that I helped put on a friend's car, it's been rock solid. I find that most problems with MS come from someone not following the directions of what the ECU NEEDS to function correctly or thinking they know better... I do agree that the lack of diagnostics was one thing that really kept me from running MS on anything for a long time, but other than the one time I had an ECM fail, due to water dripping on it, I can't think of an instance where the diagnostics actually helped me. So while I still think it's a good idea it's not a paramount concern of mine anymore.

I do agree about the reliability of the Delco being great. Other than the one failure that I've already mentioned I've never had another fail after the install is finished. I did have a couple 1227747s die on a friend's conversion way way back, when he didn't realize that the ECM had to be isolated from the chassis ground. Though those ECMs may not have actually died, but just not run right because of the ground loop. I don't recall all of the details now, but I do recall that the ECM had to isolated in the end.

I just don't see a Delco that will be easily converted AND cheap to tune by flashing. LT1 PCMs are the only ones that come to mind that kinda fall into what you want, not OBD2, flashable, and likely to run a 4 cyl. But you'll end up spending more time tutoring people on how to use the flash utility from Tuner Cat than it would be worth IMO. I do hear you about people not knowing how to install an EEPROM, but this is where people need to take responsibility for their own actions and pay attention. If you make something fool proof, someone will just make a better idiot. This is where for some people I just give them the bare essentials, and let them figure out the rest, because I don't want to be responsible for them not paying attention and then blame me. But I'm getting cynical again about people, since the more people I meet anymore seem to only be out for themselves, and step on anyone they can to get it.

The way I see it, this falls into the choose any 2 of 3 categories, Cheap, easy to tune, flashable, all 3 just doesn't seem like it's going to be an easy thing to find in the Delco world.

Have you looked at Dynamic EFI's EBL? This is a flash conversion for certain Delco ECMs, but it's not exactly cheap.