* Aid cutoff does not appear imminent
* Stopping aid would hurt U.S. defense companies
By Susan Cornwell and Andrea Shalal-Esa
WASHINGTON, Aug 16 (Reuters) - Some U.S. lawmakers are calling for the Obama administration to shut off aid to Egypt in the aftermath of the army's lethal crackdown on protesters. But untangling the aid relationship with Cairo would not be simple and could be costly ...