If it is in fact 26.0 then the manufacturer's recomend against using a mountain stem. There have been pro's and con's about this in other posts but the gist of the argument is that the corners of the half round in the stem and the corners of the face plate will create stress risers in the bar because the clamping force will all be concentrated at the interface between those corners and the bar. An inexpensive road bar for your steering tube dia will fix that problem.
As to the brakes and shifters.....you can mount road bar end (time trial style) shifters on the ends of the bar and a conventional MTB brake lever on the flat top of the bar.
If you try to mount time trial brake levers out on the end of the bar you will have the wrong brake cable pull ratio and very weak brakes. Those levers are strictly for Road Brakes.
It is possible that there is an equivalent bar made to MTB specs. Try Nashbar or Ebay looking for a base bar with a 25.4mm measurement.