Well some forums have a rule of not sharing your .RCOs; but thats just plain stupid, because they do allow 'theme's' to be released; when its the same exact thing. Sharing your RCOs.
I don't have any link to a 'dump', also you can do this yourself, with
pbpunpacker
psar dumper for 2.5 firmwares
and Sony 2.5 firmware update.
Remember, the 2.5 opening_plugin.rco is the one that is customized, so if you dont have a customized one, with 'custom sound, text, or a custom wave'.. Theres no need for you to do this.
Do you have one?
*** EDIT***
By the way
Snookao and wolf! Thanks for your comment guys! I did this because some people are having problems with this in my fiances' 'thread' and I want to make her work as easy as possible and help her out.