some options to address the problem;
1) stress-relieve the ext.ant wheelset and carry on.
2) rebuild the extant wheelset with new spokes
3) rebuild rim brake wheelset
option 3) is not very appealing because you will need new hubs and as pointed out above the spokes will need to be different lengths, so really you are wrecking a set of wheels in order to gain a set of rims which may or may not be ideal for a disc-brake wheelset anyway. But on the plus side it can be carried out 'offline' and it gives you a spare set of wheels (always handy).
Option 1) ought (unless there is a fundamental problem with the spokes or how they fit) to result in a wheelset that may break a few more spokes (essentially those which are already cracked) but ultimately should give a reliable wheelset. How many spokes might you break? Well, a small number, up to about as many as you have already broken in the wheels.
Option 2) is a good opportunity to learn how to build wheels. I wouldn't suggest that the LBS does it; the logic here is that if they knew what they were doing they would have done (or suggested) 1) already.
cheers