I don't know if John at MotoPro will tell you exactly what springs he's using in his applications. He wouldn't tell me what rear spring he was using when I told him I wanted to go to a 6.0 from a 5.8...and I understand why to some degree. He probably shouldn't have told me about the fork damping piston being the big issue in the '06 fork, because after mulling it over I decided to do the Gold Valve mod myself. I know he'll sell you the springs.

I used KLX300 fork springs on my '06 and just spaced them for the proper preload. It's of course harder to address the longer spring issue you have. I don't think anyone is making a specific spring for the '09 and later KLX250, but there is probably a proper spring in the area of application for 10" travel KDX's if you know how to search through the Race Tech or Eibach catalog.

 

I am going to see the shock guy tomorrow after work. we will take the forks apart and either remove the '09 spacer and use the longer springs or find the stock length spring from his catalogue and order them. I am going to change the shock spring in a few weeks anyway so at least I will be able to match the length with whatever I end up using on the front.
Should be interesting at least.

 

Fwiw just because susp shops don't list a spring application, doesn't mean they can't get them. They all pretty much source from the same sources. I run .49 forks, and 6.4 shocks for example.