[maddinat0r]

One could program an IDE and integrate the AMX machine into it, then compile the script with debug symbols. Break points could be implemented like that: you set a break point in the IDE and when compiling, the IDE adds a special native at that line. When code gets executed and the code executes the native, the native pauses the pawn thread. Only problem is reading data from stack, I don't have enough experience to tell if this is possible. Also if some runtime error happens it should be no problem to pause the pawn thread at the line of code where that error happened.
Almost everything is possible in theory