VMS isn't a Unix, and I don't believe you can get ahold of VMS any more. The IBM mainframes are too expensive and not open source, so there's no point in comparing them to Solaris.
What's your point exactly? My point is that Solaris is useful, even in its somewhat dodgy state (thanks Oracle for the paid update program you fucks).
OpenVMS is available. For free if you get a hobbyist license. You can then either run it on Itanium, Alpha (real or emulated), or VAX (real or emulated).
There are several Alpha free emulators out there for Windows. There's also Simh which emulates VAX servers and is available for Linux, WIndows, and probably others.
IBM mainframes may be expensive but when you're talking about mission critical things like core databases for your statement of record at banks, expense becomes a little less significant.