I've seen 400Hz systems on some of the ferries as well. Smaller transformers etc. would certainly be an advantage for distribution at that frequency.

Why 350V DC though? [Linked Image] Are they actually suggesting that this could become a standard utilization voltage in domestic systems?

It seems that would necessitate a complete new range of appliances for domestic use, not to mention making simple brushless induction motors in small appliances impossible to use.