[woodcote]

That's a concept that is used in some HO track builds, using round steel rebar wire. The slots are routed in the track surface and then the wire is pushed down using a roller and heavy pressure. The width of the routed slots is slightly smaller than the diameter of the wire and the depth is just more than half the wire's thickness. The benefit of the wire is if it is laid in - ideally - one continuous piece around the track, thus giving excellent electric connectivity around the lap. Laying it in smaller lengths could be problematic in terms of conductivity and the ends snagging the braids.

I do agree with others who have pointed out that braid will wear on the smaller contact area - that's my experience running braids on standard HO track. The vertical rails cut through the braid. Although a round wire won't have the same 'cutting edge', what may also be a problem is the braid having much less contact area on the power rail. If the braid gets a bit crooked, it may lose contact altogether.

As for tyres crossing the raised wires, that isn't a major problem with the smaller HO cars (including those running without traction magnets) on HO track. If you are looking at giving the track a textured surface (which sounds very cool, by the way), I suspect the texture will have more impact than any raised rail.