Here is an interesting video from the Barefoot College solar program in which they've trained illiterate women from African villages to be solar engineers for their communities in just 6 months:

Barefoot College makes four key points about their program model:

1. Work with the community to make sure they are willing to accept the woman as a technician before she travels to India for the training
2. Do not include "paper certified" technicians in the process, they cannot be seen as equals by the communities or the local technicians
3. No certificates - its the community that certifies technicians. Certificates only promote leaving communities for city jobs.
4. Partnership models work in rural areas - the government or donor buys the initial solar equipment and the community pays technician for ongoing maintenance

Using the numbers in the video of 60 women trained and 40 villages solar electrified for $1.4 million, or $35,000 per village, I would say that the Barefoot Engineers have a pretty cost effective program. I would only suggest that training the women in Africa, rather than flying them to India, might even generate a greater cost/benefit scale.