Thanks but I have given up on the idea of the MB Pro and will get the 11"MBA and a iMac...............problem is I dnt want to have to wait for the customized iMac 4 to 6 weeks in Malaysia so I was just trying to find out if there was a huge difference in the stock iMac or the fully loaded iMac ($1800 worth)I thought I'd chime in as I have both a Vaio Z and a 15" Macbook Pro.
To address some concerns of yours:
Size: the Z is significantly lighter and smaller than my MBP. While the MBP isn't heavy by any means, it is heavy relative to the Z.
Space: Seems to be your largest concern. You can easily mod the optical drive in the Z to fit a standard 2.5" laptop drive. I believe there is a 9.5mm height limitation, so currently the largest drive you can put in is a 750gb HD. There should be a 1tb 9.5mm laptop drive coming out later this year. So in total - if you just modded your optical bay - you could have a 750gb + 128gb SSD. The Z also now has an option for a 512gb SSD (I believe it's a quad raid 0 array).
The stock SSD in the Z is not very easy to replace depending on the model you have. Sony uses proprietary parts, so you cannot use just any old 2.5" drive in place of the stock SSD without modification. That said, if you have the cash - you can call Sony and order the proprietary 512gb SSD and install quite easily.
So in total - if money was no object - and you wanted to max out your Z and still have an SSD you would:
1. Pay the cash for the 512gb SSD upgrade
2. Remove the optical bay in exchange for a standard 2.5" bay and either buy a 750gb HD now, or a 1tb drive later this year.
Thanks