Some agents do specialize in modular homes. Many stay away both because of the comparatively low prices (and, thus, low commissions) and because modulars are a whole different market.
In my area (Northern Virginia) most owners tend to sell them themselves. And that's especially true when the homes are in a park, so the owner pays monthly park rent. In that case, really, no real estate is being sold. It's just the home itself which is title and handled just like an automobile is. (Check out Ohio laws and regulations; I don't know whether Ohio is different.)
Hope that helps.