I have a few SPARCs, actually. Those are fairly easy to find. I want a Sun-3, because to my mind that's the truly transformative device. In principle I could sit at a 38-year-old Sun 3 today and do my actual job productively, with pretty minimal workflow changes. It's one of just a handful of Devices That Changed Computing Forever, and in principle one that should be accessible to a collector. But they're rarer than I'd have expected, especially given how many I saw sitting around at school in the 90'd.

And yeah, the desktop VAXen were almost exclusively for VMS. But the standard Unix box in the early-mid 80's that everyone talked about when they discussed/benchmarked/whatever the platform was a 11/780 running 4.2BSD. Those aren't meaningfully collectible for an individual, obviously.

I love collecting old machines also <3 I have a PDP-8 and 11 replica (from obsolescence guaranteed), some of my first computers, a G3 iMac of which I just love the design, HP-UX boxes because they were really formative for me with Unix. I also owned some Sun hardware (a SPARCstation 5 and an X-Terminal) but sold it when I moved to a small apartment. I still regret this.

But indeed the servers are really hard for collectors because of the size. Similarly with the real PDP's of the day. We had a real PDP-11 at the computer museum where we volunteered though we never turned it on. Too afraid of a cap blowing and damaging more.

HP had some nice small servers later on, but they were not very influential so like you I don't really see a benefit in collecting them.

There is also the MicroVAX. We got one (a MicroVAX II) at my place of work shortly before I left in 1986. It ran Ultrix, a BSD derivative. As I recall it, the box would not have been too big for personal use, though the price tag probably was on the steep side.

From before, we had a VAX 11/750. It, too, was a freestanding box in the computer room, possibly close to a cubic meter in volume. Not something I would want at home! It ran VMS, which I found clunky and difficult to work with. But we got a Unix emulation layer called Eunice installed on it, which made it more bearable.

I'm curious; I know the Sun workstations were generally well-regarded, but what was it about the Sun-3 specifically, that made it such an important quantum jump?1

The joke (at Sun) back in the day was that a Vax MIP was constant, like an electron volt.