Hi Russell
Interesting question. Inaport has been used to pull Excel data from a URL, but never tried with text. If you send me the URL you are trying to use, I will have a play.
An alternative approach would be to have a batch process that copies the CSV file locally (perhaps using ftp) then runs Inaport. You will notice that the text connector has the ability to rename and/or move a text file to another directory after it has been processed, to facilitate exactly this process.
HTH
Regards
David