RobbBB, I want to draw your attention the the model I constructed in http://lesswrong.com/lw/h4x/intelligence_metrics_and_decision_theories/ which solves the duality and ontology problems in AIXI.

Since then I've made some improvements, in particular quasi-Solomonoff induction should be constructed slightly differently and, more importantly, I realized the correct way to use UDT in this model. Planning to write about this soon.