I got frustrated when some application I was using *still* didn't support delete properly and discovered that the solution in that community (the OCaML world) seems to be (at least for commandline use) to use 'rlwrap' to add readline support to arbitrary applications.
eg:
$ rlwrap cat
Now you can use readline features (eg delete, cursor movement) to edit text
Neat.
http://utopia.knoware.nl/~hlub/rlwrap/