Bump, here is a pack of planet "sunflares" for all your planetary background needs.
Each is high res, so you can blow each planet up as big as you need.
Unfortunately, you will need to put the sun elevation to zero because otherwise you get all the weird flare effects that result from being a sunflare.
Also make sure your sunflare color isn't set to 0 0 0 because that will make these planets not show up.
Download SunFlare_PlanetPack.zipCredit to TheRealZephyr for the images
A Preview of a couple: