Agreed. I spent some time updating the jpackage project's nosrc RPMs to work with newer versions of the JRE. There is a lot of complexity involved in making what Oracle's JRE installer delivers integrate nicely with the rest of the system.
You can download an rpm, so it should just be a matter of conversion. At least the last time I did this, you downloaded a shell script that when you agreed to the license extracted an rpm from itself.
So it should be a little more straightforward. Of course, when yoiu roll your own package, you don't get automatic security updates, so that's still a pain.
It makes it incredibly easy to create an rpm/deb/etc. from a directory, rpm, npm, gem, python module, etc.
Here's a BayLISA video about it: http://vimeo.com/23940598