All the PSP Minis are developed using the same dev-kit and environment as a normal PSP game. I find this rumour somewhat bizarre. If you've developed a PSP emulator that convincingly upscales - and I can well believe that Sony is capable of this - why limit to just the Minis?
Not saying the rumor is true, but the Minis are very simple. Some of the PSP games use ad hoc network for LAN play, which will need to be mapped to PSN style infrastructure on the PS3, or tightly integrated with the adhoc Party app.
May be we will see them someday but not now. Some how I don't think these are high priority for Sony, they sound like low hanging fruits for the moment.
