"BTW, what does the 90% mean?"
I think GfK Italy get data from 90% of stores and they just give the totals without extrapolating to 100%.
"I think there's a lot of potential for a slimline PS3 in the future"
I would expect them to release a slim PS3 when the Cell & RSX die gets shrunk to 45nm, maybe around the start of 2009. This might coincide with FFXIII release, so maybe they'll do a bundle similar to what they did with the PSP and FF in Japan. Pure speculation, but it wouldn't surprise me after seeing what it did for PSP hardware sales there.