I'm also sensitive to smells and have some skin allergies. The smell of the stamps is only there once you cut open the pack and clean it, once the stamp is made and hardened the smell goes away. I learned the hard way to use gloves when making my stamps, not only is it messy but the gel gave me a bit of a rash, as long as I use rubber gloves though I have no problems.
It's pretty expensive to have just one or two stamps produced, especially with graphics. If you're wanting just words though lots of shops on Etsy make custom stamps, you might want to search there.