lol....I still have my DR-5 from 1994! I made a ton of my old school joints with that thing midi'd up to a CZ-101 synth back in the day.
Anywayz....you could do what you're talkin' about, but the DR-5 only has 4 tracks of sequencing and the MoPhatt is capable of doing 16. You should seriously consider steppin' up to some computer sequencing. The DR-5 is prehistoric and isn't good for much more than a paperweight these days.