i like your idea, i think i got something in a book that does this, but it is for ranges something like 10R, 100R and 1K, so not so good for what you need.
also, the circuit i have i need it more for connections on pcbs, because at those big ones and complicated it is sometimes hard to find a connection.
and about putting a buzzer, it would be great if you can make it sound on 3 different frequencies, because you will have to do somethig like put the testers on the circuit and turn your head to watch the leds, thats why i preffered an audio indicator, you dont have to stare at it all the time.
good luck, and if you get something nice, share it please.