Very cool, but... I'd want it to cut through regular foam rather than polystyrene!//Poly is too breakable to fursuity stuff isnt it?

It should with woth any foam type, try looking up DIY foam cutters, if you know someone thats a bit of a sparky like myself, should be to hard to get them to build you a custom one :)

I just use an electric knife! XD hehe.. but if i wanted one, it definitely wouldnt be hard... and crazy's a lecky nut!

hmmmmm i should test out different densities of upholstery foam on the hot wire cutters at uni to see if they work with that or if the melting action sends them all munted
not a lot of faith in the guy only really cutting through sheet foam, id want something with the oomph to cut up a big block

all depends on the current going through the wire, if he jacked it up to a higher voltage, it shoulndt have a problem goin through various thickneses

thats cool. goot to see some geeky stuff. plenty of other uses for somethign like this too. If you get a slightly higher awg wire you could cut perspex and that would rock.
As far as collapsible foam goes i don't think it would be very usefull, plus it would damage the outer surface and possibly give off some shonky fumes.. go the electric carving knife.