I got a Mac Mini a couple years ago 'cause of all the different OS's I could run on it. It came with Tiger and Panther. I've been predicting OS4 running on Mac for quit some time! ;-) (not holding my breath due to lawsuit though).
What I love about the Mini is the size! Plus you can add all the stackables! Plus, the built in Ethernet, Wireless, Bluetooth, CD-RW/DVD-RW. The PPC version only has 1 RAM slot though and 1GB sticks are somewhat expensive even on Ebay.
I bought a 15" widescreen LCD for it and I use it right at the end if the kitchen table (I have all the cables bundled up real nice so you can hardly see them). It's like a little workstation in the house.
OS4 on my Mac Mini would be the cat's meow!!! That's why I bought one while they were still CHEAP and available! BTW, I had never used a Mac before I got the Mini! Over 20 years as a PC (and C64) user - man, was I frustrated for a while! Also, Amiga emulation has been WAY easier on the Mac than on any of my PC's.
I bought Civilization IV on the cheap a few weeks back when CompUSA was going out of business here in Michigan but can't play it yet 'cause I only have 256 MB of RAM. DOH! The game did let me watch the intro and it was gorgeous!
Here's what would be cool.... OS4 on the Mini running Mac emulation! Or, dual boot. Maybe even boot between OS4, MacOS and Windows. :-D
OK, enough of my morning ramblings... more coffee!