I have the lights that came with the setup, Coralife compact fluorescent, lunar blue moon glow led. Here is a picture.
I did add the cpr sr3 protien skimmer in the rear of my biocube 29 and it seems to be working fine. I saw the new hood and light for the 29 but have not found where to get it or a price.
If you contact nanotuners.com they are a direct reseller of the Oceanic BioCube line - they can order parts independently (such as hoods/lights) and get you pricing, or you can take to them about an LED upgrade depending on the type of power you'll need.
1+ Nanotuners.com has some great add-ons for the biocubes BUT putting MH inside the tight-fitting Biocube hood will cause serious heating problems in summer that only an expensive heater can solve. You mail nanotuners your hood and they can fit lighting upgrades into it. It is pricey option.
I got a Sunpod 150 watt plus shipping for under $150 and I have nice maxima clam and its doing fine.