Toys R Us sell the bikes Mashi is talking about, KM.
I don't have experience with a balance bike, but I do think that going without stabilizers is definitely the way forward - we took M's stabilizers off last year (age nearly 5) and she got it so easily that I thought it was worth trying to see if E could do it, and she is now riding without stabilizers at over a year younger than her sister was. I have a theory that the stabilizers actually hold things up because they believe they need them when they can actually learn a different (and more significant skill) without them.