A qa architect is a person who design the building block of qa process. Basically this is more relevent to test automation where many things comes in picture. S
So his role is to place and consult the optimized way to place the block so that whole system is stable economic scalable, fast and optimized.
Test automation uses a lot of resources like machines. Tools and services so this guy is responsible to stablish the system which follow the above mentioned guidelines.
QA Architect