1tufgt,Looks like the 5 LED 5050 t10 don't work for the license plate since they are too long.
Which T10 5050 5 LEDs did you try?
I just received this set of LEDs from Amazon yesterday: Amazon.com: 10x 194 168 2825 5-SMD White High Power LED Car Lights Bulb: Automotive. I got a chance to install it a few minutes ago after I got home from work. The plastic base of these LEDs are a little bit wider and thicker than the old incandescents and the previous LEDs that I had in there. They're snug and I highly doubt that they'll vibrate loose. I was able to snap the light base into the lens sockets (not sure of the proper terminology here) without a problem. The LEDs throw the right amount of light onto the license plate now.
I'll try to get a quick photo of it this weekend.