This evening I installed QNX 6.0 on my 1GHz PIII system. It has a software installer, but is unable install the AmigaOS XL package because it cannot read the CD-ROM repository. So that was a waste of time...
Next I shall try upgrading a working QNX 6.1 / AmigaOS XL installaton with the update packages on the QNX 6.2, 6.3 and 6.4 installation CDs.
If this doesn't work, there is a CD ISO image available on the OpenQNX Community Portal that contains user-contributed software, including a software installer! It might be possible to install this under QNX 6.4 and then use it as a method of installing AmigaOS XL...