The following patch will allow the Image Builder to have file exclusion lists:

Index: openwrt/target/linux/imagebuilder/Makefile
===================================================================
--- openwrt/target/linux/imagebuilder/Makefile  (revision 3449)
+++ openwrt/target/linux/imagebuilder/Makefile  (working copy)
@@ -45,4 +45,14 @@
        if [ -d ./files.$(LIST) ]; then \
                $(CP) --remove-destination ./files.$(LIST)/* $(LINUX_BUILD_DIR)/root; \
        fi
+       if [ -f ./files-remove ]; then \
+               for file in `cat files-remove`; do \
+                       rm $(LINUX_BUILD_DIR)/root/$${file}; \
+               done \
+       fi
+       if [ -f ./files-remove.$(LIST) ]; then \
+               for file in `cat files-remove.$(LIST)`; do \
+                       rm $(LINUX_BUILD_DIR)/root/$${file}; \
+               done \
+       fi
        $(MAKE) -S -C image KERNEL="$(KERNEL)" BOARD="$(BOARD)" BIN_DIR="$(BIN_DIR)/$(LIST)" install

It can have lists two different file types:

  1. files-remove will remove files from all image types
  2. files-remove.myimage will remove files from only "myimage" 

These files should be placed in the image builder's root directory.

The file can contain a list of specific files or contain wild cards.

This satisfies the feature request I made it Ticket #386.  If this patch is not in the correct format please let me know.

Cheers!