The reason why i usually search for eps as they are sharper than normal logos and it's almost impossible to find every logos i need in higher than 4000x4000 resolution and eps can solve that problem, but as it's hard to find them , i can't do anything.Oh, you go for vectors eps... I always search for "X logo" or just "X" and I find some large quality vectors. I'll try to release mine as I have some problems with specocc.