I have a Navy Federal CU card and just requested and got approved for my first 10K limit!
I Actually had a NFCU card years ago, and well, I had an employment issue that caused me to have some issues paying off my card. Eventually it closed and I worked back from it. I've had the new card for a few months now, and I planned to do a CLI, but wasn't sure how much I would request. I saw this: http://ficoforums.myfico.com/t5/Credit-Card-App-Approvals/well-well-NFCU-you-love-me/td-p/2085959
and some other threads and figured out long story short, you can request up to whatever the system has in it for you, and it will get approved with a soft pull, more and you get the hard pull notice. So instead of going the small amount requests in the thread, I would recommend going for a reasonable 3-5000 request depending on your income and your current limit.
Soo happy! Gonna keep that card at bare minimum usage!