My thoughts:
-High lift scissor or portable two post would probably be my choice of a second lift. Currently own a Bendpak HD-7P, and while it is fantastic to work on Miatas or other small cars, it's a VERY tight fit with the Supra or the LS400, due to width of those cars. Trucks, exotics, heck, even some modern American cars are simply out of the question. I'm sure this would preclude a lot of classic American cars too, but have yet to try. The other problem with a four post, it makes removing subframes... interesting, let's just leave it at that. My advice? Go as wide as you possibly can in the space you have available.
-Better advice? Plan out the building you're going to use as a garage for the eventual lift you may have. I should have extended our garage about 7' in width, it would have allowed for two lifts, no problem. Alternatively, it would have simply allowed for more room in general, never a bad thing in a garage unless we're talking about climate control costs... This advice is more or less for new or future construction plans, but still... count on having a lift someday, you won't regret it!
-Glad to see I'm not the only one using the term, "rocket surgery" haha.
-Trailer crane!!! I'm totally borrowing this idea now, thank you so, so much for sharing. I mean, I see these on service trucks all the time, how I never thought to stick one to a trailer hitch, I'll never know.
-Not all lifts require 240v, but it's not a bad idea if you can make it happen. I had a plug installed for a welder I knew I would eventually buy, so fortunately for me it works for the lift too!
-It is a pretty awesome feeling seeing a tool you put together take a car into the air, you're right about that! =)
-Under hoist stands, I've also seen them called high reach jack stands, could also be used to support the suspension ala a 4-post lift, if one needed to have the weight of the car on the wheels and happened to be using a 2-post lift. I'd suggest something along the lines of hub-stands or some other way of mechanically securing the things, as the last thing you want is a car on a lift moving when you don't want it to...
-Drain bucket would be nice to have, but the same effect can be achieved in a pinch with a stack of buckets, assuming you have lids. ;-)
Great article, has been a lot of fun seeing your garage come together!