Hi Guys,
the GW7 style convertor may be of interest.
I think it creates styles from midifiles. I checked it out briefly a while back, it's a bit complicated, and as I don't currently own a Roland, I didn't spend a great deal of time trying to figure it out.
http://www.roland.com/products/en/GW-7/GW-7_World_Styles/index.html

If your GW7's load G70 styles, this site may be of interest. http://www.selskabsmusikeren.dk/index.php?option=com_docman&task=cat_view&gid=24&Itemid=32

EMC Styleworks may be of interest if you were wanting to create styles. I have the Universal plus Package version for my psr & ketron keyboards. Unfortunately it's a very pricey piece of software.
http://www.emc-musicsoftware.de/viashop/storefront/start.asp?

best wishes
rikki