Not one useful answer to your question -as expected.
I am a cigar smoker myself (though a relatively new one) and was looking into electronic cigarettes. As far as I can tell from some of the reading I did, they are almost entirely harmless. As you of course know, nicotine is not a carcinogen and if it does have any cancer promoting/accelerating properties by way of immunosupression and angiogenesis acceleration, such effects are quite small.
I will be buying the electronic cigarettes myself personally. I get cigars from two places, thompson and cigars international and they both have electronic cigarettes. So I will probably order from one of them.
If you try them out and have any experiences to share, please write them up here
Best of luck