You can have a look at:
http://wiki.openzaurus.org/HowTos/OPIE_and_GPEit explains how to have both, GPE and Opie, running together at the same time, in different VT, so you can switch between them at will.
I used to have this setup in my SL-C3200 and worked fairly well after a lot of customization (both, because the howto is written for an older version of OZ and to fix some unexpected behaviours). In one of the experiments I did I ruined all my setup but that's another story.
But honestly, I am not sure your 5500 has enough horsepower for this (although the how to is written for a collie, I have to admit that slowed down my Zaurus, maybe because it needed more memory and I have to enable a swap file), can you post if you succeed?
There are some posts dealing with this somewhere the OZ forums, just search for them, they may turn out useful for you.
Good luck.
E