Thanks, glad to know I'm not the only one who recognized this as a legitimate issue.
I'm assuming the pads you've built have no sonic impact on the signal, because you probably wouldn't be using them otherwise. But that would be my main concern if I were to purchase one such as this:
http://www.sweetwater.com/store/detail/MAX10/
How difficult is it really to build a pad like the one you've built for a balanced XLR connection? Isn't it just a few resistors to solder? Of course you need to know the correct values, but I can't imagine that it would be overly difficult to execute.