Try the attached TXI. I added the line "bumpyshinytexture mycube", and that made it work for me. My guess is that the game didn't know what to do with a mesh that had a lightmap and a bump map but no reflection, so it just shrugged and didn't draw anything.
Fantastic work on the texture as usual! I'm just sad that you won't be able to see half of it because the ship is up high away from the player. I'm half tempted to add a similar ship on the ground somewhere else to show off the rest of it...
DP_I-Wing.txi