Yes, Parrot has a similar limit
I think that it is 64 registers each of 4 different types.
And yes, there was a stack as well, but each item contains a whole set of registers so you only want to do that when you really, really want to. When I saw "was", I'm admitting that I saw the design before they added pervasive continuations to it. I don't know how continuations have changed things, but I know that it isn't a small change.
So the obvious implementation of Forth is pretty much a worst case.
Cheers,
Ben
"good ideas and bad code build communities, the other three combinations do not"
- [link|http://archives.real-time.com/pipermail/cocoon-devel/2000-October/003023.html|Stefano Mazzocchi]