If you're willing to reflash all the way up to the eMMC, it takes literally a minute to edit your eMMC image with a hex editor, to get yourself an image that gives you up to 9GB of /home partition space. (Technically you can cram more, but 9216 is the highest 1-GB cut off you can get when your max number is 9999, so yeah. <--- this makes more sense if you actually read up on how to edit the eMMC image)

There's a bunch of methods in the wiki explaining how to partition it even without reflashing though. I just did this method because I was reflashing my N900 including the eMMC at the time.