A few of us here in the office have been looking for a portable Bluetooth speaker that will work in the shower. Alas, G-Project's $69 G-Go (G-100) speaker, which is available in Target stores, is splash-resistant but not waterproof, so it might not quite fit the bill. But it's close.
The speaker comes in blue, black, or white, and has an integrated handle for carrying it around, which makes it look a little like one of those industrial flashlights. There's no built-in rechargeable battery like some portable Bluetooth speakers have, but you can get up to 8 hours of on-the-go use with four AA batteries.
You can stream music to the G-Go from any Bluetooth-enabled device, which includes virtually all smartphones and many tablets, including the iPad and higher-end Android tablets (the and do not offer Bluetooth).