Brett, the only thing i can suggest at this time is a under lug or barrel mounted clamp on laser/rail. This will probably not be too practical due to the "nature" of the 500. I am waiting to see if crimson trace will ever put out a grip Laser for the 500 which would be very nice.

There was a spot to request production of ct grips for the x frame but don't think demand was ever high enough. I have 2 of the 500's. Guess it wouldn't be bad for the 4". Not sure how well a trigger guard mounted laser would hold up to the recoil.... if one is even available. While the 500 x frame can use k grips the key cuts on ct k grips won't fit the x.