*If you're concerned about salmonella poisoning, use a pasteurized egg. These can be purchased, or you can make them at home (Google it).
You can prepare the meringue and crumbs ahead of time and freeze them, if desired.
Obviously this ice cream takes a lot of add-ins, but also obviously, you don't have to do all of them. Customize this ice cream according to how you like your s'mores. I highly recommend the peanut butter.
If you don't have an ice-cream maker, you could probably freeze the ice cream mixture in ice cube trays and then blend the cubes in a high-powered blender (let the cubes soften slightly if they aren't blending well). Stir in your add-ins and refreeze until firm.