Overkill for softies, yes, but it would also leave plenty of spare power if you want to add more light demanding creatures. A 4 bulb would likely be sufficient, even if you started adding LPS. However, if you end up with the 6 bulb you could simply leave 2 bulbs off at all times and only run 4 of them. If you have spare cash burning a hole in your pocket and want to experiment, you could use the 2 spare slots to run a different bulb combo and alternate throughout the day.
As for mounting, I can't recall seeing any tank mounting legs when I had been looking at different fixtures. Those unfortunately seem to have gone away. I think there was a recent Geisseman fixture that had the option.
Aquatic Life does have some mounting arms that attach to the back of the stand that allow you to use a hanging kit. I picked up a couple of them for my T5/LED hybrid upgrade, but I haven't gotten around to installing so I can't yet comment on their quality. Others have crafted up similar DIY setups with PVC, conduit, or other materials.