I started using Kodak's TMAX Direct Positive Developing Outfit in order to process my own B+W Super8 film. I tried it on a roll of 35mm TriX and loved the results. You'll need to experiment with the timing somewhat if you use anything other than TMAX100 since that what the instructions are written for. (I got good results from TriX by increasing the first developer time by about 20%)

I have successfully made B+W slides from TriX, PluxX, PanF as well as processing various movie stocks.

I usually find the kit at FreeStyle for around $35.