sequencer software

["Tim Goodwin" <deepbass@earthlink.net>]

Hi Looper People,

I am doing some work with complex rhythm permutations and I'm looking for
the perfect software to help me compose large numbers of MIDI files.  I 
have
been experimenting with different MIDI drum sequencers with some
disappointing results.  The best software I found seems to be a something
called KeyKit.  It is a graphical programming language that allows you to
create custom consoles for unique MIDI applications.  But the program seems
to be a bit unstable and requires quite a bit of knowledge of its own
programming language to debug.

Anyway, I have found that I need certain features in a program:

(1) A matrix interface to select note on/off values for rhythmic pieces.
Ideally, the subdivisions are customizable to at least 64 and a time
signature select function would change the column label of each step to
match the beat reference.

(2) I would also like to apply specific patterns to each track with a 
single
command (every beat, every 3, every 1/2 beat, etc.) as well as the ability
to cut and paste patterns to the grid.

(3) The ability to customize the single command patterns that get applied 
to
the tracks of the grid would be especially ideal.

(4) Notate the final result with the option to select a separate staff for
each instrument.

(5) Ability to save the grid and notation as image files.

(6) Save the final sequence as a MIDI file.

Does anything like this exist?

Thanks,

Tim