You know what? I'm actually working on a (very abstract) universe simulator.
It's only a computing model at the time, implementing it on nowadays computers 
would be either inefficient or impossible due to the amount of space needed to 
simulate a universe as big as ours. At the moment, it could help analyze and 
understand the first moments of a brand new system, but if you want to simulate 
something as complex as a sentient biological individual living in a viable 
environment, I think you'll have to wait for the emergence of quantum computing 
(and still, with such computers, the problem of space would still arise).
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>you break my heart, anon. I don't need an entire universe... just her. You are 
telling me it will never happen?
...maybe? I mean, you can't possibly create more matter in a closed system than 
what's available in your universe. For your dream to come true, you'd have to 
find the minimal amount of energy needed for such universe to possibly emerge 
inside your simulator... Probably far less than our actual universe, the 
emergence of life here wasn't optimal after all. So, strictly speaking, it's 
not impossible. Just very difficult.

However, this theory doesn't exclude the possibility of another universes 
outside ours. But then, physicists would tell you that in order to break the 
barriers, the geometry of this universe, you would need more energy than the 
total of the system. Unfortunately, you'll have to use your imagination for 
this one.

Imagination is already quite a powerful thing, is it? Being able to see and 
feel something that doesn't even have a physical incarnation with so little 
energy compared to the whole universe is quite a chance for me... And maybe a 
curse too...