wahaha..
i a bit famous on ipod condoms hor...
hehehe.. anyway, i think the thinnest will be the zcover which is 0.6mm. it has a plastic screen protector which is rather clear but to wad extend i do not know. anyway, with the thickness of oni .6mm, it would not really help in protecting ur ipod frm bumps.
for the iskin evo3, it is rather thick but then again, i think protection is more important for my ipod.
lastly the price for the zcover is USD29.95. if u ship it frm the USA, it would cost u ard another USD5-10. if you really wanna get one and a bit cheaper, i suggest u head to ebay.com

wahaha..
not advert my stuf... i like those accs n to get them... it is cheaper if we bulk... hheehhe

anyway, i think if u wan a real transparent skin then u need to get the crystal hard cases de..
hehehe

lajo..
not very sure of the thickness.. u can search for the bulk in the bulk section.. find "doubleclick" cos i think he has it