Short answer is no, I don't think they exist. Rhythm sections are cheap to add to a keyboard which needs the amp and speakers anyway. All the drum machines etc that I've come across assume the user will be using some form of amp anyway and are built accordingly (though I'd be happy to be proved wrong).
Best I can come up with would be something like the Zoom MRT3-B which is about £80 from Soundsalive and comes with 396 patterns, trigger pads, umpteen drum kits etc. Couple it to a small practice amp or use headphones.