It was possible to take almost any game and make a package to run from the xmb. All these pkg's stopped working with the release of ofw 3.56, and no one has yet made the same method possible. It would seem that sony are and will in the future be able to block this method of packaging games to be launched from the xmb.
The cut and dry of it is, in answer to the original question, yes you can for 3.55 and below, but for ofw 3.56 or higher forget it.
I have seen some on usenet that are presented in this form but if you can get yourself to cfw 3.55 and stay there for the time being.
The xmb pkg thing is outdated and no one needs to be that worried about there bluray drive if you are using backup managers.