RIM is making one last push for content for its BlackBerry 10 platform after announcing that it will double the reward money for developers that take part in its final ‘Port-A-Thon’ to $2 million.

The events are hacking sessions aimed at encouraging developers to port their apps for other mobile platforms to the upcoming new RIM operating system. Developers are given $100 for each app (maximum 20) that is approved for the BlackBerry World app store; those that submit five or more apps enter a draw to find a Limited Edition BB10 device.

The company has used the Port-A-Thons to boost its app eco-system ahead of the Blackberry 10 launch next month. This week, it revealed that its most recent one saw more than 15,000 apps submitted over the 37.5 hour period. While all of that figure may not be approved for the store — which is what triggers a developer to get the cash — it is a promising number, and, by making more money available, RIM is looking to give the strategy one final bump.

The RIM posting explains more details about the kind of apps that can be ported:

What apps are eligible, you ask? You can build/port apps using any one of the development languages that supports BlackBerry 10. Port from Android, use HTML5, Native C/C++, AIR, jQuery, Marmalade, Qt, PhoneGap, Appcelerator, Sencha and more. Additionally, apps created using BlackBerry App Generator are also eligible. (Note: you need to own the blog content to be eligible)

Documents leaked this week show RIM is expecting to have 70,000 apps in its BlackBerry World app store when its upcoming BlackBerry 10 devices go on sale in February. RIM passed 3 billion app store downloads last July but content for its devices has been a real Achilles heel for the platform, since many of the top apps and services for Android and iOS aren’t available on its phones. That’s largely down to a lack of technology support — primarily no touchscreen — or simply perceived low user numbers on the RIM platform.

With the introduction of touchscreen devices running BlackBerry 10, RIM is hoping to bridge that technology gap and encourage developers to build for its platform as well as the others. It has built a range of porting devices — central to the Porth-A-Thons — to make the process as easy as possible.

The long-awaited unveiling of the BlackBerry 10 series is scheduled for January 30. RIM execs have confirmed that they will release phones sporting touchscreens and keyboards to please their traditional followers and hope to win new admirers. Equally as important, the company will introduce lower priced versions of the devices, primarily aimed at emerging markets, in due course.

Related: RIM opens Built for BlackBerry program, reveals Qwerty BB10 Alpha device, rebrands app store

Headline image via Justin Sullivan/Staff