DMUs and Locos - Bring me Up to Speed

OK, I am interested in trains and railroads, but ot so much that I know every detail or am up on every development. I know Amtrak has looked at several DMUs, Colorado Railcar supposedly offers them but I have yet to actually see them in service, and several companies supposedly offer them but have yet to sell any.

So what is currently available for passenger service rail vehicles? I know on the large loco side GE and EMD sell passenger locmotives, but are there any smaller units that are more efficient for smaller-scale passenger routes?

And in DMUs, what is currently available? There's the Talent, which I understand isn't FRA compatible. Besides the CRC, is there anything in service that is? What about the Rohr Turbo trains? What happened to the flexliner and that japanese one that was supposed to go to south carolina?

I know on the large loco side GE and EMD sell passenger locmotives, but are there any smaller units that are more efficient for smaller-scale passenger routes?

MotivePower Industries (MPI) has sold quite a few of their MP36 Series locomotives to agencies such as Metra and CalTrain, and Alstom has sold its PL42AC locomotives to NJT. Both of these locomotives use EMD engines, but the design of the locomotive itself came from MPI and Alstom, respectively. However, these units aren't really any smaller or more efficient than the ones from EMD and GE. They might be less expensive, though. (I'm not sure.)

Photo of the MPI passenger loco:
http://www.railpictures.net/viewphoto.php?id=68600

Photo of the Alstom passenger loco:
http://www.railpictures.net/viewphoto.php?id=138895