Have to say that when I identified the Volvo hub cap years back I was convinced that the rim was in fact the base metal and had just reflected the blue colour can anyone confirm ? Have been meaning to get round to make one of these looks amazing bud.
quick cheap and lightweight, make a headband out of card make sure its a little loose, inflate a balloon inside it at the height you want then cover in strips of newspaper painted with pva/school glue build up a few layers let it dry for a day or two and you have a decent base burst balloon job done
you could sand out the whole crackle pattern and repaint the whole handle using the crackle paints there are a few threads around on how to go about it
don't know how feasible it is but shapeways have a section with their own software for designing your own rings i don't know how complex you can go but its an option worth looking at
model painters tend to use tamiya clear red with a little black in the mix, I've also heard of mixing it with a little glue for the clots and even a bit of hair thrown in, some use a gloss clear coat other don't bother, theatrical blood does'nt tent to look so good dried as it can gel and...
have you checked out the free paper props section as there is a whole section devoted just to Potter stuff and is chock full of stuff as long as its for personal use you can print off anything your heart desires