Besp iPad solution for drag-and-drop MIDI import/song building (drums)

[coloroo]

Hi, I'm looking for suggestions on a MIDI sequencer app for building up a drum part. I have a bunch of Groove Monkee general midi drum loops that bought and I would like to be able to use in some iPad app for putting together some songs. Ideally the app would have the ability to browse through the rather large tree (thousands) of different MIDI files with the ability to preview them, and then drag-and-drop/import them sequentially measure by measure to build up a song. Ideally the interface should be rather painless without having to go through a lot of contortions to do this. Extra kudos if the app also supports odd time signatures. Thanks.