I didn't do the grinding with my own two hands, but gave the nod and stood by watching as the guys at my local indie nipped the ends off in seconds flat. It sucks, in that it shouldn't really need doing if the damn things were designed correctly, but i don't believe the modification structurally compromises the bar, so I just decided to do it anyway (as there are no other big bars out there for the C6 to try instead).
If you want part numbers, try here
2007 Audi A6 Avant Quattro Applications || H&R Special Springs, LP . Not sure about the etiquette for posting direct links to online store pages, but I can tell you that I sourced mine via Larkspeed. A word of warning: the wait for them to made and shipped to the UK was
immense! You may have better luck, but be prepared for at least a few months of lead time

Again, I think we owe that pleasure to the C6 not being a commonly modded vehicle (in comparison, to say the C5 or B6/B7), so they only make stuff to order.
I hear you on the wear side of things with the bushes, but there just didn't seem to be anyone making them for what is essentially a big executive express - bags of straight line go for sure (esp. with a remap), but not exactly a car that many people mod as a track-day/hill-climb weapon

That said, I'd probably grab a set and give it a try if I could find some (for the same reasons you say... I like that feeling of "taughtness" and a sharp response from the tiller).
I'm obviously going soft as I head towards middle age, as these days I draw the line at anything that requires drilling into the body... ******** to that.