Nice idea.
Whats the points cost? Where is it, the tourney that is?
The core looks nice, although for a themed scout force i would be tempted in using a basic master over the shrike stats as he may stand out like a sore thumb. I understand you want the all infiltration i guess. If you took a basic guy with minimal stats you would bolster the Ld of the force, without any risk. Shrike does this but he will be involved and you WILL lose him as he doesn't have the support of his squad, and nothing else you have is that fast. Expensive HQ to throw away.
Scout bikers are nice for eliminating close hard targets in the first turn (such as tanks), but as a unit to hold the line you might find them a bit poor due to their save. Also as you will be infiltrating most of the army first turn, they will be countered easily. They do however fit into the theme nicely. I have found them ok at best, and not had much success at tourneys with them.
The Tornado squadrons are good, and put out a bag of fire, but as you say you will be missing some anti-tank.
I would consider:
1: Dropping shrike to a basic guy, and give him CCw/Bolt Pistol (saving ~80-100 points). Keep him hidden, boosting the Scout Ld.
2: Take a small squad of scout bikers. Keep hidden and use these as a mobile scoring unit to seize objectives in last turn. Give them meltabombs in case a tank gets too cocky).
3: Take 2 x tornadoes as you describe.
4: Take 2 x tornadoes with MM/HF combo
5: If you dont like the scout bikers, consider another squad of tornadoes, or if you feeling luck with you, go with a pair of typhoons. The blast/HB combo is sweet on packed troops.
6:The points you save with dropping the 2 tornadoes from the speeder squads, and from shrike, will be enough to get you a predator destructor (with HB's) or two. These will give you rolling forepower, 2 more scoring units and they fit in with the scout theme as they are not the heavy combat version (annihilator).
I have seen a similar list played by a guy in Utah and it worked well.
Its hardly math-hammer as you arent fully kitted but if you follow my ideas, you will have 12 units, 11 scoring.
you could of course add an inquisitor and an assassin