The templates used in the Biswal 2010 paper are included with the scripts. They are in the folder called "templates". Those templates are all 3mm. However, 2mm ones are included when you download and install FSL. Resampling those to 4mm should work for you.

The ADHD200 preprocessed data are an initiative from the NeuroBureau. Those data include the ADHD200 data preprocessed through several other pipelines (except the original scripts).

Maarten