If you want high light at the bottom you are faced with getting a high powered LED
. BML or ecoxotic e-series are both good choice but expensive. One other alternative you may or may not have considered is LED
floodlights. They are really cheap right now. I don't know if there's any PAR data out for the larger wattage ones, but the smaller ones look promising. The 30W led
floods are on amazon right now for $18 with free shipping over $35.
I have used them over 40bs and had no problem growing plants. I have one over my 2ft tall 120, if I were running just these I'd probably get 3-4. As to how effective it is, not sure, it's still fairly new in that configuration.