Alan, I do not know if this has been asked for, or noted previously.
It would be nice to run commands asynchronously:
[NSThread detachNewThreadSelector:(SEL)aSelector toTarget:(id) aTarget withObject:(id)anArgument]
and that runs the command in the background (with potentially an activities panel). This would be really useful when making large builds directly from TM's interface.
Currently the UI blocks until the command is completed.
Nick