Ah the DS Trainer. That shoe entered my training rotation a couple of times. It was a nice (different) feel than the more cushioned shoes in the mix. At some point I realized I was no longer young, light, or fast enough to accommodate having this model in the stable.
None of that really helps you with finding an alternative though. The first version of the NB Fuel cell Prism was low bulk and peppy (like the DS Trainer) but with more shock absorption. Of course, the Prism no longer exists, so it also has that in common with the DS trainer. I tried on the NB Supercomp pacer (which is a carbon plated racing shoe), and it felt a lot like the DS trainer. But, it’s a racing shoe, so maybe not what you’d want for training.