Looking for GB compatible "long form" sequencer

Hi all-

I'm looking for a "long form" sequencer with a few requirements:

1) I'd like to be able to automatically generate a preselected number of measures and/or time length at tempo

2) I'd like to be able to fill those measures with any/all of the following:

2a) a predefined sequence,

2b) a random sequence of some sort (possibly predefined with "rules" ?)

2c) a generative sequence (predefined)

2d) Would LOVE arpeggiation

3) Generate GB-compatible MIDI

Been looking around, and I see some very cool stuff, but am not nearly as familiar with these functions as some of you probably are. I guess it would be helpful if all were included in the same package, but individual apps/plugins are fine too!

Thanks!

Andrew