( I simply think that U-Bolts make a sloppy looking install. )
Why not create your own. Considering the fact that most roll bars aren't round but are rectangular, all you need are some tasteful looking metal and some stainless bolts of proper length.
A hacksaw, drill, maybe a grinder for smoothing up the cut edges, rounding up the ends. A few hand tools, maybe some paint.
I can see a simple tasteful metal bracket, with the top piece of metal being just long enough to span the ROPS, with a hole on each end. A piece of matching metal cut longer then the top, drill 2 holes near the center to match he holes in the upper bracket, drill 2 holes near the ends of the lower backet to attach your lights to. Round off the ends and any edges for safety and appearance, spay paint everything in black if you so choose, let dry and install with the stainless bolts.
Make a pair of these, one for each side of the ROPS, bolt 2 lights the the front holes and 2 lights to the back holes.
You can buy several sizes of black plastic wire loom. I think I used 3/4". I also used a 7 conducter insulated cable used for trailer wiring that I placed inside the loom.
Most local hardware stores sell several sizes of flat stock in both aluminum and steel.