I REALLY don't like the pop in grass in Oblivion.
I have edited the .ini, and changed fGrassStartFadeDistance= and fGrassEndDistance= to 12000, but there is no noticeable effect. Is there a mod I can get that will increase the distance grass renders? The pop in bothers me a lot.

It's an engine limitation. The pop-in happens no matter your setup.

It is possible to remove the "pop up" effect by adjusting the ini

You can't extend the grass but you can make the grass "fade out" nicely so that when a new cell is rendered far away grass doesn't "pop up" from nowhere.

I use the following settings

iMinGrassSize=10
fGrassEndDistance=12000.0000
fGrassStartFadeDistance=5000.0000
fTexturePctThreshold=0.1000

hope this helps you

-dan

Also, also using HDR lighting is supposed to make grass fade in gently rather than just pop in. I've never actually tried that myself though.