I second pelican cases. Have my tools in some of them and have used them for various other things through out the years. I even use them as suit cases when going on trips. I have a few cases that are 10+ years old.
there is definately no beating pelican.....best on the market as far as I'm concerned. The only problem with them (really not a problem i guess) is the weight.....they are a little heavier than you might expect when you start getting into the larger ones. In my previous life, I used some BIG ones.
and really, any case you choose, consider weight. those shipping cases you linked to are light, but that plastic can be damaged much easier than a pelican. when you get into custom cases, alot of times, they use plywood with sheet metal overlays. the size of the case dictates thickness, which of course dictates weight.
i would start by laying out all your instruments how you would want them organized in the case. that will give you a really good idea of the actual case size needed. Don't forget to leave room for expansion, and change. nothing worse than making a perfect package, only to find that it doesn't easily adapt to change.
Let us know what you decide......I've been kicking this idea around too.