This post contains no TES music, only music to musicians and instruments it could have been cool on.
To hear the Skyrim theme in an electric guitar on all it′s glory you′ll need at least two guitarists
You obviously haven't heard Jorge Caballero: http://www.youtube.com/watch?v=cHAVgOf_-aE - quite extreme... I'd even call arranging it for guitar in the first place is impossible - guess someone forgot to mention that to him though
Also check out part 1. I think he would be perfect candidate for making and playing a Skyrim guitar arrangement
For the more beautiful and less powerful Morrowind theme, I don't think anyone comes close to Ioana Gandrabur when it comes to emotion in musical arts: http://www.youtube.com/watch?v=LvL9xaUqZGA - would love to hear Morrowind in tremolo style, which few would do as good as her
Not serious though, but I wonder how "mutilated" Yuja Wang could make the themes go if she could "have her way" with them: http://www.youtube.com/watch?v=j1fgo7hp-Ko - it sure makes me wonder
Another one of hers: http://www.youtube.com/watch?v=8alxBofd_eQ If you wanted to "jazzify" the themes, I'd say Fazil Say would be the man to have a go at it, his own style. Here is what *he* did to Turkish March: http://www.youtube.com/watch?v=0_Whp1kWZ8Y
For the unusual, I think Morrowind theme in a Theremin and Brass combo could be sweet: http://www.youtube.com/watch?v=3EcAiTE0JyE (more normal application of Theremin: http://www.youtube.com/watch?v=ePzPpPmgeSU). For the utter outragous - Skyrim on the Chipophone maybe? http://www.youtube.com/watch?v=gAuPIgD-TM0