I think you would be happy with any leupold, the bushnell elite 3200, the weaver grandslam, upper end burris scopes, middle to upper end nikons, or simmons aetec's.
I highly recommend the hammer extensions. Makes life much easier, especially in the event that a new shooter needs to de-cock the hammer.
I would go with the one's from Virgin Valley as they are made from aluminum and shouldn't weaken the hammer spring over time.
Regards,
Smoky