Digital Multi-tracker looping?

[cwb@platinum.com (Clark Battle)]

There are three MiniDisc 4-track machines on the market
now (Yamaha, Sony, Tascam (next month), (Fostex cant be
very far off)).  With very quick access to any recorded
data it seem like these machines could be used for looping
quite well.  Does anyone know if any of these machines
can loop a section of music on one track while recording
on another?  I know some tape multi trackers do this as
an auto-rehearse function but, of course, you have to wait
for the tape to rewind.  It seems like with a little bit of
memory to cover the seek time of the MiniDisk, auto-rehearse
could be used as a killer looper with saved loops!  Is it
a feature on any of these machines or am i dreaming?

Clark