I think it's a great idea and can't see how it's disrespectful to the dead. Having recently lost my nan, she would have thought it was a fab idea, she hated waste of any kind and would be only too pleased to be still being useful in her death (she loved to be "useful" and busy).
Once I'm dead, hopefully not for a long while yet, I couldn't care less what they do to the empty shell that remains, it will rot in the ground or could be used for something more useful, won't matter one iota to me, I'll be dead!