Create a calc field (type text) = container. This field will show the file name and maybe more info about the file. In that case you can extract the file name from the calculation field.
If you want to remove the container field itself from the layout, you need a button with 'Insert File' script step to enter files into the container field.
OK, that sounds a bit harder than I expected. Maybe I will tolerate the icon for a bit longer while my develop my FM skills.
If I use a calc field and if I use the Insert File script button, is it possible to have a field that contains several files in list -- without having a portal to a separate table? (Again, trying to mimic the Bento file list field.)
Update: I notice that if I set the container properties so that the image icon is "cropped" -- and then resize the container field so that there is just room for the filename text, then I don't have to look at an icon in form view.