Yes, ridiculous for you to pay the premium. But a great opportunity for you if you need a top-tier Mac and know how to upgrade RAM & HD -- which is the only way I buy mine.
From the company's standpoint, it makes sense: lower entry-level price; higher profit margin for items sold to those with more $ than tech-savvy. ::Keeps the company profit margins high while giving the self-upgraders a nice break.
If you notice the new RAM/CPU tray, on the quad-core entry level MP they only give you 4 slots for RAM, whereas on the 8 core they give you 8. I'm not sure if there is an extra socket on the tray to pop another CPU in or not, but I wouldn't be surprised if the answer was that you can't.
So it seems like you can't just buy the entry level and upgrade it past the top level on the cheap this time around, which is something to be upset about.
With a Mac Mini, I'd need to get special tools (some kind of spatula I believe?) to get the damn thing open, and run a serious risk of ruining my warranty. Same thing for my girlfriend's iMac, at least for the HDD (you need to remove the screen with glass handling equipment apparently) - the RAM is easy at least, which was the main worry, there's always gigabit ethernet and the file server for disk space.
From discussion I remember reading way back when the g4 mini was originally launched, this will not void the warranty, but take that with a grain of salt.
I thought the same thing, but it turns out the cheaper one only has 128MB for video, the more expensive one has 256MB.
I've been playing with the idea of getting a Mac Mini to replace my current media PC which can't handle HD video, but it looks like I'll still need to open it up if I want a decent spec.