Audio tubes!!! Please!!!
I just wanted to say, this is a fantastic app. I've designed the PSU and switching circuitry for a guitar amp that I'm currently building, and so far, iCircuit has been absolutely spot on when it comes to the scope voltage and current readings. I was a little sceptical to begin with, but it's all knitting together quite well.
But the one thing that I'm missing that'd make it perfect for what I want is a collection of audio tubes. Not all of them, obviously, because there are way too many variants, but would it be too much to ask for the usual ones - 12AX7, 6L6, 6V6, EL84, EL34 for starters? From reading similar suggestions, I think I can almost guarantee that you'd generate plenty more sales!