Insurance on an EV conversion is a common question.
The simple answer is YES you can get insurance, and look before you start the project.
I had no problem getting insurance on my electric car conversion through Progressive. I was also using a full-service insurance agent, and explained to her exactly what I wanted to do before starting the project.
Other things to check on before you start your project include, license, title, registration, pollution control tests, and local, state, and federal laws.
Rules and regulations vary considerably from one area, county, state, country, to another, so look to see what applies to you.
By planning ahead, you can have a project you are proud of AND be able to legally drive it!
Here's a few more comments on it at my blog.