just bear in mind that all these filaments with metal are considerably weaker than all plastic filaments. And the more metal they have - the weaker they are.

For a lightsabre handle you might want to look at the reprapper tech (I don't work for them honest lol) metallic filaments. They use metal as a proper colourant. But use a lot less than the colorfabb filaments that need to be sanded, while looking a lot more metallic and costing less.
They even do flexible metallic filament. Got some flexible copper that just looks like a roll of thick copper wire.

Sample wise keep an eye globalfsd.com - not much they don't carry :-)