Don't have one, but I know how to make a decent conversion.
You'll need a SM chest piece, an unbuilt XV25 to butcher, a FW head (I recommend breacher) and a pair of shoulder pads.
First you file off any imperial insignia off the SM chest piece, to make it bland.
You take the unbuilt XV25, and take the engines off the body (the two come attached). you need only the engine.
After that point, assembly should be rather obvious
If you got another shoulder pad to butcher, you can take out the tau symbol and place it in the center of the chest piece.
This is the end resulthttp://images.dakkadakka.com/gallery/20 ... %20Tau.JPG