Greening electricity pylons

In 1999 it was reported how important small ponds were to the conservation of biodiversity. Environmentalists have much regretted the destruction of landscapes by electricity pylons, associated with the loss of hedgerows.
Electrical pylons may be used to create habitats for a range of species by suspending suitable containers in which appropriate plants might grow to encourage certain insects and nesting birds. The challenge would be to design around the real and spurious constraints imposed by electricity authorities.
In the case of the ubiquitous vertical concrete walls of urban environments, plants can even serve to inhibit graffiti. The species on pylons could even be of interest to the farms which they traverse as habitats for pollinating insects. They provide protected habitats for birds.

There legitimate reasons why species should not be allowed to climb or dwell on such structures.
Are there unexplored windows of opportunity for niche creation in modern constructions -- as is the case with wrecks on the seabed? Have electricity authorities run tests to determine what these might be in the case of pylons? Greening pylons might significantly improve the environmental image of the electricity authorities as well as beautifying the landscape.