Do we need to have a single letter? Is it acceptable to combine prefixes?
Eg: 1 QB (quettabyte) == 1,000,000 YB (yottabytes) == 1 MYB (mega-yottabyte)
Without the new prefixes, we could have gone to 1 YYB (1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000, or 10^48 bytes)