Regards white labels, I’m not sure as to what solutions are currently available but I do know that it is a lot harder than it at first seems.
However regards no-download casinos, Chartwell and Wagerworks are both “Flash” no-download options, while pretty much all Microgaming casinos offer a Flash version of their casinos with a subset of their games. Also, RTG and Playech both do Flash versions though these are generally a fair bit slower than the download versions.