Yeah, I would guess NA at least will be receiving the 40gb in a few weeks seeing how low weekly sales are for the 60/80gb models. The 60gb will eventually disappear and the 80gb will see a price drop (although all of these moves might not occur simultaneously). If the 40gb flops in Europe, I bet we'll see the 80gb with BC enter as a 2nd SKU. Nothing is ever set in stone, especially PS3 configurations, so if BC proves important to consumers and said consumers prove it by not buying the 40gb, BC will be back.
I think the 40gb will be a success, albeit not a huge one. When this comes out in NA in November like the rumors say, I think we'll see around 50,000 sales per week for the month until Black Friday, when sales will hit 100,000. This will still mean the PS3 will lag behind the Wii and 360 which will hover 'round 100,000 and 80,000 per week respectively. I think this is solid move by Sony because I know a couple people interested in the PS3 that don't give a crap about BC because they were planning on keeping their slim PS2s around anyway.
My Top 5:
Shadow of the Colossus, Metal Gear Solid 3, Shenmue, Skies of Arcadia, Chrono Trigger
My 2 nex-gen systems: PS3 and Wii
Prediction Aug '08: We see the PSP2 released fall '09. Graphically, it's basically the same as the current system. UMD drive ditched and replaced by 4-8gb on board flash memory. Other upgrades: 2nd analog nub, touchscreen, blutooth, motion sensor. Design: Flip-style or slider. Size: Think Iphone. Cost: $199. Will be profitable on day 1.