I've installed several theme packs to emuNAND on N3DS AND O3DS, first had about 90 themes, second which I just got last night had 108. They all work, and it's very nice with the theme shuffle feature.
Edit: The only catch is that you have to uninstall the previous theme pack with big blue/red menu first. I think you can install right over it too, but you cannot install say one theme at a time. You can only install a theme pack or a single theme as they will over-write one another.
Edit Edit: Also, make sure it's for USA, not J or EU. Themes are region specific it seems. I'm not sure about 200 themes for US. I don't think there are that many yet but could be mistaken.
Pretty sure we got them from the same place. I went with the full collection instead of the split collection