Total Commander

I love how TC enables me to add files to a move/copy list using the F6 shortcut, and then choosing Queue.

Is something similar available for FTP uploads?

ie. as easy as selecting a file, and hitting a button to put it in a queue. No need to edit lists or anything.

If not, that's my suggestion.

Yes there is:
1. Commands - Background transfer manager
2. Connect to the ftp server
3. Select the files to upload
4. Alt+Tab to the Background transfer manager
5. Press "+" key or "+" button in the dialog
6. Choose "Add selected files for uploading"