If we are still talking about vocals the low-shelving will probably work for most pop/rock performances. I might leave it alone though for a barittone singer. Another thing: in most cases the MICROPHONE'S low-shelve switch worked better than the pre-amp's one. Cleaner and with less coloring. If you have a microphone with a low-shelve switch try that as well (or at least record something in both manners to see which one works best for your project).
2-3dB gain reduction is perfect for what you want. It will serve you well on most cases. In time, you might even get down to 5-6dBs, depending on the singer and the genre (you know; the guys who scream "I HAAAAAATE YOUOUOUOUOUOUOU!!!!" for 2 and a half minutes in front of your mic!). Don't go lower than that though, unless you REALLY know what you want, because everything here is irreversible.
I think that both the Neve 1073 DPA and and the SM7 are great alternatives to the Liquidchannel and the MD421 respectively.
I'm not sure about the BOCK 241 though. Not because its not a great mic, but because it can't compete with the U87 in terms of the "client factor" you mention. ("Whoa dude! Is that a Newmann mic and a Neve pre-amp there? Cooool!!")
Vain as it is, even my grandmother knows these brands! (well, not exactly but you get the point...)
The compressors are quite expensive as well. But I guess you can't settle for less if you are talking about such mics and pre-amps. Maybe later, you are right on that one too!
Thanks for your perspective...
Things that matter in life are not things.