Well, here are the results of the test. It was rather illuminating (Ha!), and I decided to sacrifice the bar to see how hard I could push it.
50mA - 10.7V
100mA - 10.9V
150mA - 11V
200mA - 11.1V
250mA - 11.2V
300mA - 11.4V
350mA - 11.5V
450mA - 11.6V
500mA - 11.6V
550mA - 11.7V
600mA - 11.7V (started rapidly heating up)
650mA - 11.7V (too hot to touch, starting to smell funny, few chips have gone dark)
700mA - ~8V (cascading chip failures, was actually rather neat looking as they flashed and gave out in sequence)