dunno of anything like that with an in-built metronome...
but yer the smokey amp + metronome would be a good option...
the smokey amps are so fun lol, i got one a while ago... so cool to mess around with... also i think its possible to use it as a fuzz-box kinda thing with some amps but it reacts really differently with certain amps... for example... it sounds pretty cool through my mates AVT but through my crate it makes me want to cry...