I'm not familiar with the epic feat, but I might try to convince my dm to give me a feat to let me get more SR. I'll be 15th level, so I have an SR of 25. What bonus to SR would you consider reasonable for a preepic feat?
If your DM wants to stay close (scale-wise) to the epic rules, the non-epic feat would be either +1 (& selectable many times), or +2 (& only selectable once), IMO.