Theoretically I see no reason, why iron (III) chlorate could not exist. Making this in practice seems a lot more difficult to me. One route could be to make a dilute solution of chloric acid from barium chlorate and sulphuric acid (BaSO4 precipitates out, leaving HClO3 behind). To this solution you add a freshly and thouroughly washed precipitate of Fe(OH)3. What you get is Fe(ClO3)3. Keep some excess HClO3 in order to keep the solution clear and free of hydrolysis products. Careful drying (evaporation) at room temperature in a dissicator over conc. H2SO4 may yield the desired product.
I do not believe that Fe(ClO3)2 could ever be made. If it could be made, I would not like to be near a bottle of this stuff, which contains more than a few hundreds of mg of this compound. Fe(2+) is quite a strong reductor and ClO3(-) is a strong oxidizer.This compound (if it exists at all) would be extremely sensitive and could easily explode due to internal oxidation/reduction. For this reason, Fe(NO3)3.xH2O is a simply available, commercial chemical (also available for the general public from some photography suppliers), while Fe(NO3)2.xH2O is a very unstable lab-curiousity, which is really hard to prepare.