This isn’t going to be anywhere near as easy as you are hoping and planning for it to be. Simply having various 1080p sources doesn’t make this work.
I think both Darth Lucas and I realized how incompatible the SSE is as far as just dropping in some of the shots into the BD. For instance, everyone wants the Dewback or Sandcrawler shots replaced. Switching from the BD to these shots will be immensely more jarring (OCD or not) than the way Harmy has done it.
For 2.7, I checked out most of the shots with GOUT element to determine whether or not using the SSE would be an improvement. In some cases (such as this http://l1.picsurge.com/cCwnAo/pDP6EP9rPb.jpg ) there is no question that it helped the picture quality. I replaced most shots that were 100% GOUT. There are some shots that, with the SSE scan, just aren’t really improved as much. Keep in mind that to get them looking even as okay as they do in 2.7 required additional automatic and manual cleanup on top of what TN1 has already done, as well as grain reduction, sharpening, color adjusting, and stabilization. And that was for only a few shots, as opposed to every single specialized shot in the film.
You need to consider how many shots Harmy had to use just a small GOUT element with the rest of it staying Blu-ray sourced. You’ll be downgrading the majority of the shot in those cases. And then the whole shot will switch back to blu-ray and the quality difference will bug you. Unless of course you’re planning on rotoscoping all of the 35mm elements into the Blu-ray footage. In that case, you’ll be working on essentially what exactly what Harmy is doing. This would be a very long project, and Harmy will probably have better scans when he does it, resulting in less of a drop in picture quality.
I think you’re also making light of the immense task of color correction. I think you’ll see from threads like Dr Dre’s that this is no trivial task. I don’t think anyone has a color corrected blu-ray that’s ready to go for you. There are some works in progress. But as far as I know, most of those projects are going to feed into Harmy’s work. So, although it will probably be a very long wait until Harmy’s 1080p, GOUTless 3.0, I really think you’ll be better off waiting than trying to tackle this yourself.
If it really just is a desire to be rid of GOUT/97SD elements in Despecialized, you can have a go at removing the remaining GOUT sources from 2.7 just for the hell of it. It’ll be 720p, but it’s feasible. I’ll be happy to point out what’s left. And if this actually turns into a viable project I can send you the lossless 2.7 files I guess.
Alternatively, since the main thing bugging you is shifts in quality, and I don’t think your proposed project will help that (rather, it will make it worse), the SSE on its own might just be the best version for you. Hopefully 1.5 will be out soon and have some nice improvements.