This really awesome feature
It would autopopulate the phone number from Contacts to Jobs. Please!?
You can already access the phone number from the contact while on the job:
Web: Hover your mouse over the green “Related Contact” bubble and click on the green portion to see the phone number there.
Mobile: Tap the call button in the bottom action bar when on the job page to call the Related Contact phone numbers.
These should get you everything you need for this feature, but let us know if you need something else!