How can I deactivate Find my iPhone's Erase iPhone?
Apple doesn't provide a way for you to withdraw an erase command from iCloud. Theoretically, if it hasn't been withdrawn, an engineer for Apple could go in and remove it from the queue assuming:


They could verify you were really you
You figured out how to convince them to do this


As for whether you can still track the device after an erase is sent, that depends on the version of iOS on the device. 

If you have iOS 7 or later - the erase action does not stop tracking or remove the activation lock preventing a thief or someone who finds / buys it from being able to use the device. It will still show your lock message and you can still track the device. Problem solved!

If you are on iOS 6 or earlier, you are correct that you will have lost the chance to track the device once it connects and receives the wipe command. If it ever connects to Apple's servers, the wipe will happen and the device will be erased and you should get an email if/when that happens.