I'm using a Diamond hot end but I haven't actually tried different materials. However, it is on my list of things to try but my ageing, creaking Mendel variant is busy printing parts for a new printer that I'm planning.
You are right in your assumption that it is perfectly possible. If you look at the drawing of the Diamond you'll see that the "mixing chamber" is 0.4mm diameter x 2 mm long so it doesn't take much to purge. As well as support materials, some of the ideas I have is to use exotic filaments for perimeters and standard cheap PLA for infill. Also, maybe try using electrically conductive filament to lay down tracks within the object being printed. There are a lot of possibilities................