If you have an old single-core Atom netbook lying around try clocking it at 1GHz and see how SSF runs. This would give you a very rough ballpark idea of how a similarly optimized version would run on a 1GHz Pandora. My expectation based on what little data I could find is that SSF won't run most games well even on a 1.6GHz single-core Atom netbook.
The amount of work needed to even port it to ARM Linux may be high. Depending on the recompiler design a conversion may not be trivial, and even a more straightforward effort would involve a fair amount of busy work. Any hand-written SSE code would have to be converted to NEON which may fit poorly, and even where it maps nicely there's definitely a learning curve involved for anyone uninitiated with NEON. Especially if you want to get it to run well on Cortex-A8s or A9s. I think the graphics are actually all software rendered, so the issue of porting from DirectX to something that runs on the Pandora (hopefully direct framebuffer access) may not be as big of a sticking point as it sounds.
To be totally frank, if the allure of Android and/or iOS hasn't compelled him to make an ARM version already, and he wasn't already drawn to the Pandora then I doubt he'll be very interested now. What Pandora and the rest of the ARM world really needs is a new highly optimized, preferably open source Saturn emulator. Ari64's work porting his excellent recompiler to SH2 and Yabause was on the right track, but it takes a lot more than this for Saturn emulation - you need very efficient VDP1 and VDP2 emulation and Yabause is a far cry from having either.