Thank you, I thought I had forgotten something there. I will adjust it accordingly.
On the topic of Allips:
1) First of all the point of this challenge is to assign the cost to this strategy. What is the minimum XP/ gold required to make the Allip and then control it?
2) The Allip can run indefinitely, as it has no constitution score, which means that it travels at a maximum of 4*30 = 120 feet per round.
Once per minute the Tarrasque can move at a speed of 150 feet. This means that each minute (if running) he can travel 1320 feet. He can run for 35 rounds (his constitution score) before making any checks, then he can run for an average of 12 more rounds before he fails his constitution check and stops running. He will only move at 1 move action per round for the next minute before running again.
This cycle lasts a total of 57 rounds (47 running, 10 'resting') In those first 47 rounds he travels:
5*150*4 + 42*20* 4 = 6360 feet
in the 10 rounds of 'rest' he can only travel:
150 + 9*20 = 330 feet
6690 feet in 57 rounds, which comes to a speed of 117 feet per round.
If the Allip were run for 56 rounds, then charge and attack on the 57th, he could cover 6780 feet, giving it just enough distance to attack the fleeing tarrasque once every 6 minutes or so.
It (seems) that 1 evil cleric with an allip would (eventually) destroy the Terrasque. Interesting.