You can't really fault the shop for not promising that they can fix it. You're basically just asking them to look for a needle in a haystack. I'm sure that once the problems are found it will take 5 minutes to fix them, but finding the problems has already taken you many hours and it's going to take them many hours too, and they have bills to pay.
Are you still getting no spark?
Have you ruled out engine block grounding issues?
I'd remove the alarm completely, if you haven't already.
Is the check-engine light lit? If so, what are the codes?
There's probably a way to test the signals going from the ECU to the coil packs, but I don't know what it is. But if you can find a way, then that would at least tell you whether the problem is between the ECU and the packs, or if the ECU is holding back because it's not getting some other signal that it considers essential.
EDIT: like a cam or crank angle/position sensor, for example... though I'd expect those to trigger a CEL with an explanatory code.