Little Machine Shop offers an extended rack to allow for more travel so I planned to buy one of those but was spent out so I needed a quick, cheap fix.  I solved the counterbalance problem by taking a short piece of 1" x 1/8" flat bar and cutting it and drilling two holes in it to relocate the mounting point for the counterbalance spring. 

In the above picture the head is about 1/4" from full travel up.

To solve the rack problem I simply relocated it down one screw hole because the vertical support was already drilled for the longer rack and the screw spacing was the same.  This meant that I could now get down low enough that a mill holder would almost touch the table but it also meant that I couldn't get as much height between the spindle and the table so I knew I would still need the new rack when I could afford it.  In fact I have since bought and installed it which is why the above picture shows so much travel. :-)

Of course the torsion springs they're using with these mills now are practically useless so replacing that is on my to-do list of upgrades!