Ah. Well, I'm not aware of any specific threads for the grenade reticle, but there are a few packs out there with new ones.
http://forums.legionsoverdrive.com/threads/phanakapan-dot-edited.4671/
It seems all the other ones have expired download links, unfortunately.
I could re-upload pullute's reticles and the collection of reticles(made by Immanent I think) for you
It has plenty of reticles for you to choose upon.
EDIT: Pullute's Reticles ; The collection of reticles
here's a few threads that you can look into, i'm pretty sure they've all got a ret for GL
http://forums.legionsoverdrive.com/threads/unofficial-mod-thread.545/
http://forums.legionsoverdrive.com/threads/my-favorite-reticles.2073/#post-36039
http://forums.legionsoverdrive.com/threads/beta-trooper-reticles-v3.1751/#post-29659
http://forums.legionsoverdrive.com/threads/ultraraptors-pack-1-2.1427/
http://forums.legionsoverdrive.com/threads/reticles.2364/#post-42476
http://forums.legionsoverdrive.com/threads/kusa111s-mods-page.821/#post-18822
http://tribalcombat.com/Legions-Overdrive-downloads/?page=1&sort=1 (has multiple pages)
http://forums.legionsoverdrive.com/threads/legions-mod-list.4/#post-23