If a character has something like the Touch of Golden Ice feat (Book of Exalted Deeds, pg41) could an evil character use bluff to avoid the ill effects, or is there an item that already does this?
According to the epic level D&D rules, you can use Bluff to fake your alignment - with a check DC of 70:
However, this only affects effects that detect alignment, which could be interpreted to exclude attacks that work on alignment, like Smite Evil.
You could also craft a magic item that permanently grants the spell undetectable alignment. The item pricing guidelines suggest a price of 2,000 gp for this. However, the spell only applies to divinations like detect evil.