The back is connected with screws so it should be a simple thing to wire in another switch and, if I'm going to bypass the internal batteries, the switch can be on the incoming power wires.
Due to other priorities, I won't be installing them for a while and, since my build is for occasional, short-term use only I may just use them as is, perhaps with a Velcro mount as Ray suggests.
It's nice to find a well made product for a reasonable price. I think I'll pick up another set for work light use before Costco sells them out.
I don't know the color temperature, but they may also work as a video/photo light source.
2005 E350 Super Duty Ext Wheelchair Van
2002 Itasca 35U Motorhome