clear fablon (got mine off ebay) as a cheap alternative to copter tape. not as indestructable but has a bonus of not being frustratingly expensive if you drop it on the floor prior to applying
single layered on non vulnerable areas, double layered where needed. it's worked good for me the last 18 months, especially on the crank arms. oh, and yea, you will need a chainstay protector whatever you choose.
I regularly get vehicles 'wrapped' for signwriting purposes. This involves a lot of intricate vinyl being applied. Would anyone be interested in getting their frames 'wrapped'. You can get some amazing finishes these days. Imagine getting your frame wrapped in tiger fur. When you want a change you either re-wrap it of peel it off.