Any of our dual radio access points can provide mesh @ 5.0 GHz and provide client access (to WinCE Handhelds in your case) simuntaneously at 2.4 GHz. Roaming in an Aruba system is centralized at the controller within the system.
I have many Aruba deployments with WinCE devices and warehouses (aka. barcode scanners of varying form factors) that work(meaning roam) fine, even when mounted on forklifts, skateboard carts (fun!) or on belt clips/armbands where personnel walk around all day long with the devices.