I absolutely agree with Feline. I am a handquilter for about 20 years now and of course I have a callous - but it is quite small.
I think it depends on the hand quilting technique you use. I don't use a thimble at all and I don't prick my finger! I push the needle quite deep through the layers and so I'm sure I can feel it on the back of the quilt and the stitch is visible there.
My fingernails are also short and it works. Just in case you come to North Germany one day I would be pleased to show you my way of quilting! :-)