Ahem. Sun boxes were originally Motorola 68k based. Then came Sun 386i. Then came Sparc, which they still produce. There has been a big movement toward x64 though.
I don't know if I'd agree with equating a 'Unix Distribution' with a 'Linux Distribution'. All linux distributions are a lot more similar to each other than man unix distros. At least linux distros all have a related kernel.
The box is surprisingly standard though. Normal bios even, none of that openprom terminal. Powersupply and sata connectors are weird though. Sata connector has 4 channels on it, and a hot-swap backplane attached to it.
Also, I got some code to compile today. Pretty sweet! However, I don't have root right now, nor do I have openAL, which I pretty much need root to install.