I just create my own and save them. I have a bunch of them saved on FS9 and I'm slowly building my list on FSX. It's real easy to do. I use a name pattern of IFR/VFR_(From ID)_(To ID)_Method (Hi, Lo airways/GPS/VOR). I create flight for small and large aircraft and most are there to challenge my flying skills or my flight management skills.
"Guard well the words you use, for they can be the keys to your freedom or the manacles of your slavery." - me
Conduct a search here on simviation, type in the name Bill McLellan , he has done a series of long flight plans , they are available separately or in a consolidated package. In my opinion they are brilliant.