Hey all. So, first thing i thought of when i saw the new Space Marine Hunter/Stalker kits was "What can i make with those awesome new bits?" Well, ive figured out one thing...the Hunters missile launcher makes a great Thunderfire Cannon! (Sorry i dont have pics for each step

)
What you'll need:
Skyspear Missile Launcher bits from the Hunter tank.
2 track units from a cheap Robogear model
(link to an ebay selling the tracks i used here)
Foam insulation or foamcore board.
2 lengths of 80mm ling brass rod.
Various other Space Marine and
SM vehicle bits
Step 1:
Easiest step in the conversion. Assemble the Skyspear Missile Launcher following the instructions provided in the box.
Step 2:
Using some foam insulation or foam core, cut out a square 60mm long, and about 70mm wide Use whatever thickness you like (I used 1").
Step 3:
Using a sharp knife, roughly shape your foam so it looks more like an
STC hull (sloping front glacis, overhanging rear, flat sides). Now take your track units, and lightly position them, pushing an indention into the foam (so you know where to attach them later on).
Step 4:
Carefully cut rectangles of thin plasticard so you can form the armour plates for your Thunderfire Cannon's chassis.
Step 5:
Gently push the lengths of brass rod through the foam following the marks left in last step. These form the 'axles' holding the track units.
pics for steps 2-5: (notice i carved out an area for the ammo feed to rest in)
Step 6:
Glue the Skyspear Launcher onto the hull, and add extra Space Marine bits to taste. Using an old brush, paint white glue or PVA onto all seams and exposed foam (or else run the risk of destroying your work with your first coat of spray paint).
Step 7:
Glue the track units onto the brass rods.
pics for steps 6 & 7:
Step 8:
Using Liquid Green Stuff, fill any gaps still visible on your nearly finished model.
Step 9:
?????????
Step 10:
PROFIT!
Ok, busted...it was only 8 steps.
Hope this tutorial was helpful, its my first humble submission to dakka tuts in 4 years of being a member. And in case anyone was wondering, i plan on magnetizing the Stalker so it can be used as either a heavily armoured siege Rhino, or the Stalker (magnetize the side armore, and the turret, and your done).