One option could be having an option to place the corner crop marks x mm or x inch INSIDE the print.
I like that idea too. I usually buy premade frames, 16 x 20 with an 11 x 14 matte already cut. (Just for my own use.)
I have a devil of a time trying to hold my A3 paper with the 11 x 14 print and try to see through it to center it in the cutout of the matte.
In the meantime though, I'll bet that Terry can make a cutout frame for Qimage that will have crop marks, and perhaps then allow you to add a B+ border of 1/4 inch to the print.
Just thinking out loud!!
I am not a cut out maker.... so I cant make one, but I tried one of Terry's frames, and if there were crop marks added to the cutout frame, it should work fine.
Fred