And my response back to SF.
Ken, Richard, and Brad - First let me thank all of you for helping to get us to this resolution! This does make me happy!
Ken - This was the response I was hoping for initially. I fully understand your position on the unit being in 100% working order. I was never able to replicate the issue in a controlled environment either. It only happened in the field, as I'd mentioned. The frustration for me was knowing it'd been going on since mid Feb, I went back to check the first failure date. I recorded around 20 shows from Feb to May with 13 failures and 7 complete recordings. In some cases with different decks and the same ST350. The frustration I conveyed in my emails was the result of several months with yourselves and with Sound Devices and neither being able to replicate the issue. From your perspective it probably seemed I was coming off a bit harsh very quickly. I can assure you it was built up over time and is not typical for my demeanor. Part of the frustration was due to a breakdown in communication with Pieter, mainly due to testing timing delays, brief email updates, and lack of thorough discussion on the matter at the beginning. I can assure you I would'nt have been so adamant about a replacement had I not experienced those issues over time. I'm not typically in the business of sending back perfectly good unit and paying $60 to put a stamp on a box and ask for a replacement unless I feel it is warranted. This seems to be a unique situation, I'm glad we came to an amicable resolution.
The only untested variable remaining are the actual batteries themselves, and they came from Soundfield as well. If the problem persists, I'll test each battery and see if there's a single culprit. The resolution presented below, does make me very happy though, and want to thank you for going above and beyond to test the unit. I am aware of the labor and cost involved in your testing and want to let you know that is not going unnoticed or appreciated.
Thanks to each of you for getting us to this point!