Im looking to put in a 120 volt ballast too.... Are European ballasts for 55 watt about the same size as American ones?

This lamp is (according to datasheet) of similar length to 36W PL-L. I think it can fit in something like a 600x600mm MH lowbay body, big lanterns for 2x250W Merc lamps like Koffer 250, or some particularly tall posttops

The 230V ballast is a plain choke (requires also ignitor), and is smaller than an 120V autotransformer ballast would be. Most likely you will be able to ballast it with FL ballasts. The lamp needs 600ish mA. Maybe you can get there with slimline ballast or some very underdriving 32W Instant Start ballast with 2 outputs wired in parallel