I'd still like to see this functionality within the Catalyst MIDI implementation, but I just found out that, in the ipad ForScore application that send MIDI out to devices like the Catalyst, I can create a collection of MIDI presets at various popular BPMs that will issue two MIDI tape tempo commands separated by a delay time in milliseconds!
So for 120 BPM, I'd send a Catalyst CC Tap tempo message, then a delay 500ms, then another Catalyst CC Tap Tempo message. I get my amp tomorrow, so I will test this out.