I must blame Fonso again, because he asks me about something like FlashGot but for Opera in Linux, i.e., a way to be able to select a block of RapidShare URLs to download them with a premium account with a download manager. So when I didn't find anything, I started with it.
I finally got a bash script that receives a list of links as parameters and adds them to Aria with a RapidShare premium account. Using aria was not a choice, since it was the only one, apart from wget, that supports RapidShare premium accounts (i.e., HTTP authentication) without problems.
The script will be downloaded in any directory, for example /usr/local/bin and to add it to Opera you should edit menu configuration file located at ~/.opera/menus. By default, it will be something like standard_menu.ini. If you don't know what's your file, you can see it in Menu Configuration option. If you don't have a menu configuration file, you can create it in Tools -> Preferences -> Advanced -> Toolbars -> Menu setup -> Duplicate.
You have to add the following line in the [Hotclick Popup Menu] section:
Item, "Download selection"=Execute program, "/usr/local/bin/downloadthis.sh", "%t"
Assuming that the link is located at /usr/local/bin/downloadthis.sh, otherwise, it will be replaced by its location.