If you knew exactly what you wanted, I suppose you could probably get it from Sigma Aldrich. However, it will be listed as something like "isoamyl acetate" and

If you knew exactly what you wanted, I suppose you could probably get it from Sigma Aldrich. However, it will be listed as something like "isoamyl acetate" and not "banana flavor", so you would need to know exactly what you want. Also, make sure you get an edible/food grade version!