A http://www.scei.co.jp/saiyo/part/part11.html has appeared on the Sony Computer Entertainment Web site, looking for individuals to test "new model game hardware."
The Sony job listing says, "Experience an in-development game console (hardware) early!"
To quote: Job duties include checking on, reporting on and giving input for a in-development game hardware. The listing's Q&A reads: "This is specifically for a new model and unannounced game hardware for PS3, PS2, PSP and its peripherals."
Note: In the original Japanese text, Sony separates those hardware platforms with commas only (there's not an "and), making it somewhat vague whether this is new hardware for each or all three.
This is a full time position. It starts this March and looks to run a year. There's a one month trail period, after which those awarded the position can look to make over ¥1,000 (US $10.70) per hour. Travel expenses are covered, and there's the possibility for a raise. This position is in Tokyo and is not open to students.
This very public job listing might get more fuel to those very persistent PSP2 rumors. Though, it also might simply be more a continuation of the current PSP and PS3 hardware iterations: slimmer with more memory.