I've had great results with the Roland DR880 There are hundreds of rhythm styles, and you can also include bass lines as well. Also included are guitar effects processing, so you can plug your guitar in and play right through. There is plenty of flexibility if you are ambitions, to create your own drum tracks, or bass tracks, and save them to memory.
Short example of some slow blues with the dr 880
This is a really old recording of me when i first got the Dr880

That dr880 also allows you to run midi files thru it. You can get some great bass, drum and key sounds from it.

Look at the Zoom A2............