In fact, though, I would think that an 8051 vector would need to be profoundly simpler than a supercomputer vector; not just differently sized. When you're dealing with 1-16k of RAM and not much more ROM, a full "vector package" isn't what you need, but rather a really, really limited vector package that only does exactly what you need and no more.
In fact, you probably want a version with an 8-bit "length" value -- or even a 7-bit length with some other relevant flag stored in the final top bit, for space optimization reasons.
Source: I was the lead developer on an original Game Boy game, which ran on a CPU that, IIRC, was roughly an 8053 (it had instructions somewhat related to an 8080 or Z-80, lacking all the 16-bit instructions, but adding an 8-bit fast-memory operator reminiscent of the 6502). Back in those days you didn't have "packages." You had code snippets (in assembly language, of course) that you shaved bytes off of to make them fit. And then you shaved more bytes off.
[edit: clarity, and note that it's the Game Boy I was talking about; originally said Game Boy Advance, which was an ARM CPU. Also did a game on that device, but it was the Game Boy I meant to describe.]