looper-friendly MIDI sequencer?

[eric <eobertha@inreach.com>]

howdy.
I use MOTU's Performer (not DP) - a not-so-aptly-named piece of software
IMHO.  Interested in actually performing with malleable MIDI situations,
I have found that a simple act such as vamping on a particular measure
of a sequence and then continuing on to an another vamp on down the line
a bit is possible (with Perf.) but akward.  The memory loop points are
designed (as is the Polar function in DP) more for creating than
performing.  So I am frustrated.

Here is an example of a software user interface that would turn me on:
little whirlpools dot the screen - representing loops; lines are drawn
between many of the spirals - representing transitions.  The idea is
simple:  click a spiral and you loop, click a line between that spiral
and any other and at the next loop end (like a drum machine (a feature
sorely lacking in Performer)) the music follows a precomposed transition
to another loop pool.  The system could work for a single song or an
entire reperetoire.

Has anyone seen or heard anything about anything even remotely like
this?
Is this doable in MAX?  Anyone interested in designing some software?

carry on,
eric o.