[tubesrule]

Fableglade: The power grid was quite a confusing mess in the US and Canada into the 30's. There was no standardization even in a single community, and power could be 25Hz, 50Hz, 60Hz, or DC. By the 30's most big cities were standardized to 60Hz, but rural areas were still mixed into the 40's.

Fableglade/Darius: These are good suggestions for standards. The 441/25 should definitely be included, and I would think dropping the early prototype US standards like 120/24 and 240/24 for the early European 180/25 would be useful. (don't know how many of these sets survive, but for completeness..)
I have had suggestions for the 819 standard, but will need to look into this one to say for sure how it would be done. Right now all the output standards are smaller then the input video, so there are only downscalers in the converter right now. I think it would be a relatively simple matter to handle the 819, but it needs to be looked at.