Neko is a promising portable/tiny/fast VM which Haxe, a C/C++/C# like language, uses. Neko is plenty fast already but the next version will make it even faster with a builtin JIT. Neko uses a C-like language as well as an XML-based language for intermediate language format. For Ruby-fans, there is an ongoing ruby-to-neko compiler project.

Haxe is interesting in that its compiler can turn Haxe code into Flash file (SWF) and JavaScript as well as Neko using a mix of implicit generator and explicit library calls. I haven't look at it's dynamic generation capability though so I don't know if it can be used to generate SWF bytecode or javascript dynamically.

Current expectation is that Neko with JIT will be even faster than LuaJIT which, along with Lua 5.1, is resparking interest in Lua.