the special north american approvals CSA and UL are not a must, a lot of products have only CE and they work very well in Europe, so i think this is not the biggest issue.
I don't like the idea that there is maybe a transformer between your 120V main supply and the 230V ballasts. Are all transformers suitable for high inrush currents? Or may there occur other problems, maybe with the different frequency (60Hz/50Hz)?
I have a understanding problem, maybe you can explain me your electrical system. As far as i know there are 2 voltages in USA - 120 V and 240V - is that correct? Has each household 2 different nets?