2 that I know of.
The Yamaha TSS-1, it's a 5.1 setup with 4 channel analog inputs, and coax and optical digital inputs complete with dolby digital and DTS decoders.
The Video Logic DigiTheatre DTS, it's a 5.1 setup with 2 channe analog inputs, and coax and optical digital inputs with DD and DTS decoding.
Just FYI, you won't be able to tell the difference between DTS and DD on the TSS1s, and I seriously doubt you will on the DigiTheatre DTS either...these kind of speakers just can't output that kind of clarity.
rmblam:
The functionality of DTS is the same as DD. They are both ways of compressing and encoding multiple channels of audio into a single bit stream. Whether hardware or software, they both need decoders.