A cheap VPS with any FTP daemon will do the trick. The usernames of something@somethingelse.com are a 'feature' of basically every shared hosting environment.
Alternatively, just about any CPanel based webhost will let you do this. Just log into the FTP with your 'main' username (your host should give you this), and everything should work okay.
Alternatively, just about any CPanel based webhost will let you do this. Just log into the FTP with your 'main' username (your host should give you this), and everything should work okay.