Why a "MacAir" doesn't make any sense:
A "MacAir" simply does not make any sense. Why? Because a smaller MacMini (MM) implies losing the optical drive. This change would introduce prerequisites to owning a MM: 1) owning a owning a host PC for software installs, -OR- 2) purchasing an external Optical Drive.
At present, the MM has the wonderful selling point of being a self-standing PC. If, suddenly, it were to require having another computer or external drive around just to install software, the MM goes from being an "all-you-need" petite PC to being a "not-much-smaller" incomplete PC, which needs another piece of hardware to function fully. Let's explore these options a little more closely:
1) Having a host PC is a burden, especially when it isn't in the same room as the MM. If you wanted to install software, you have to go into another room to do so. If you want to rip a CD, you have to go into another room to do so. If you want to watch a DVD, you have to go to another room to do so. Every time you want to do something with a disk, you have to go into another room.
Or perhaps a family only has space for one family computer. What would they do then? They would have to go into the attic/basement/garage, dig out their old PC, and reassemble it... simply to do one of the aforementioned simple activies on their MM. Their only other option would be #2,
2) buying an external drive. Why would you buy a PC without a disk drive if you had to keep an external drive attached at all times anyway? Or I suppose you could only attach it when you needed it, but then what? Put it in a drawer, inactive? Why add another step to what should be a simple process? Why remove a piece of hardware that's just going to be added back again. The purpose of shrinking the MM would be to make it more visually appealing, no? (Certainly desk space is not an issue with today's MM.) Well, it's not very visually appealing to attach an optical drive via donlgle.
Also, this method would be the ONLY way to burn a disc, be it an MP3 CD for one's car, or a DVD slideshow made via iPhoto. Of the entire iLife Suite, in fact, 4 of the 6 programs utilize the optical bay in a significant capacity. For iMovie it's just about almost mandatory, and iDVD... well, duh.
The omission of an optical drive from a desktop computer makes nary any sense at all, at least at this point in time. Are online software downloads becomming more popular? Yes. Are other forms of media distribution (i.e. USB flash drive) gaining traction? Yes. However, there are still people that don't have high-speed internet connections, and even some who don't have ANY internet connection. And there exist some software offerings that are simply too large to cost-effectively fit onto USB flash or other media. Optical media is still too vital to be ripped from our desktops. Plus, introduction of BluRay - yet another form of optical media - will extend the lifespan of spinning reflective discs for another ten years. Despite how frequently or infrequently you may use it, it will continue to be the most wide-spread and cost-effective way to store data for many years to come.
The omission of an optical drive in a future MM would not better the unit in any way, and, in my opinion, would be a grave error.
Despite all the criticism to the contrary, I personally have two reasons to think a smaller Mac Mini is actually a good idea.
[parapharsed:]
1) cheaper-than-laptop portability
2) Custom installs
Niche and more niche. The MM is not meant to be a portable. It's meant to be a fully-featured, petite desktop. While I honestly do commend your unique use of the computer, Apple should not use your rare example as a model for a future computer. Secondly, custom installs, "carputers," etc. are
extremely niche markets. As someone who is interesting in performing such an install myself, I still would not condone Apple's transformation of the Mini to fit such a market. Again, it would help few at the inconvenience of many.
-Clive