Again, what phones like the n900? There's only one. I wasn't responding about speed, the topic was portability.
Without the proper supporting cast (compiler, drivers, shared libraries, ..., etc.), has it ever really mattered? Python's a better answer than Dalvik. Source code compiler and byte code compiler properly stay close to each other, and source code distribution is optional. A Python JIT is rarely considered based on how easy it is to either create Python bindings, or actually directly access native shared libraries. In practical terms, Dalvik's best features are its memory and blob management, and maybe its security, but not its portability.