depends on what you mean by customizable. i'm also going to assume you're planning to use this with a guitar or bass.
every major manufacturer offers a multi effect unit. the higher end models will allow you to assign effects in different chains to the triggers. most also offer some level of customization for each effect, so you can adjust the speed of the delay, the gain on the distortion etc.
here are 86 choices to get you started
guitar multi effect pedals