If you want to make a suggestion to add more custom rewards then the Uservoice site would be the best place to make that suggestion https://twitch.uservoice.com/
One alternative you may wish to look in to would be creating an extension that fits your needs, as then you can have any number of reward options. There’s no real integration with Channel Points yet, but even with what’s currently available to us you can still integrate channels points on a very basic level with an extension.