It's possible to remote control Amazing Slow Downer and Sweet MIDI Player for iOS using MIDI.

The best such device we have found is iRig BlueBoard which is a wireless MIDI pedalboard for iOS (and Mac) that allows you to control Amazing Slow Downer and Sweet MIDI Player from the floor.
For more info click here.

It's also possible to remote control using "page turners" such as "AirTurn", "PageFlip", "iRig BlueTurn LE" or other similar devices that are in fact "BlueTooth Keyboards in disguise".

iRig BlueBoard Bluetooth pedal

Sweet MIDI Player for iPad - configuring

iRig BlueTurn LE pedal

Amazing Slow Downer for iOS - configuring

"Page turner" pedals are configured by selecting the "Physical Key Commands" option and then selecting a command and pressing the pedal.
The pedal must first have been paired with your iOS device.

Some other suitable Bluetooth pedals are described here.