earmonger: I would guess the limiter starts to kick in around -12dBFS. Depending on how risk-averse or not I feel, I usually want my peaks to be in the -6 to -10 range).
I've definitely recorded louder shows (at line-in at 3.7 - 6.5) with DPA 4061 with the same 9V BB without bass distortion problems as long as I left the limiter off.
From what I've read on TS, the DPA converters output 5V DC. Using 48V (or perhaps even 12V) would fry the DPA 4061s based on my reading here.
I took a big chance and pulled Godflesh last night from the front row with the 4063s into M10 PiP mic-in @ level=2.0 @48kHz. Sounded fine on a hyper-detailed headphone setup (Benchmark DAC1 Pre > Sennheiser HD 800) although there was a 1.6ms window with 35 clipped samples in the left channel, but no more than 6 consecutive clipped ones, so I couldn't hear it, at least.
What I do notice in many of my recordings is distortion in the mids/highs, but that could be the mics picking up distortion in the PA system that my earplugged ears did not notice.