@farazarif
LOL
You HAD to bring up the "adoption" issue once again, right? 
On a more serious note, the issues which you mentioned with regards to the LS1 are very much there.
Maintenance. Shouldn't be a huge issue, since in essence, it's a "new" engine. I don't think it's going to be a daily driver, either...since in these days of soaring petrol prices it'll be difficult enough just to run the beast. This will keep it low on requisite maintenance needs, hopefully.
Repair. Versions of the LS engines (notably, in the Cadillac Escalades and Chevy Corvettes that're dotting the country) are already en vogue. Repairs WILL be costly, if you break things (as in all vehicle-related matters)...but WON'T be impossible. All the more reason to use it sensibly, and preserve it, as far as possible (yeah...right. Who am I kidding? :))
Usability. This is the most pertinent point. We don't have any racing tracks, for which this beast would be most suited. Our roads are decrepit. Our traffic is pretty ill-organised. Unleashing a car like this on the roads (broad, long, seriously quick) is going to have its own problems, and falls very far from the realm of practicality. I realise that. But then, this is a project that begs to be taken to extremes. For nothing else, perhaps, than to set it apart from the other Impalas in the stable. In that way, it follows an evolutionary curve. I mean...once you've built a car, you aspire to build a rocket-ship, not a bicycle. 
As far as the assorted bits and pieces of the LS1 are concerned, basically, we're getting the entire engine bay less the radiator. The tranny is going to come meshed to it. All wiring, air-flow, headers, harnesses, reservoirs, filters, fillers and dipsticks are going to accompany it, too. And the gentleman who's arranging all of this has given me a cast-iron guarantee about its worth and efficiency. As a (partial) gentleman myself, I believe him when he says this, or this project would never even get off the ground.
Thanks for the advice, as always.
Fouad.