I've got CubeCart running in PostNuke on my site now. I used the hack listed above as well as another small mod that I purchased to allow login using their email address. now, when my users go to the store, their account info is recognized via their email or username from the site. Maintained the single point login I was pushing for with pnPHPbb and
PN.
CubeCart so far has been pretty easy to work with.
I need to figure out a way to steal the *featured product* block in cubecart and add it to the main page of the site, similar to paypalcart.
KP