Also is Digi-key or Mouser the only place to purchase these? I try contacting Intel sales here but I never get a reply...
Intel dev kit provides one year warranty coverage.
I am sorry to hear that you don't get respond from Intel sales team. Typically the dev kit boards are sold by Intel distributor. Yup, mouser and digikey are 2 of them.
Feel free to check out Intel distributor list below and you can engage them for dev kit purchase enquiry. Else you can reach out to digikey or mouser also.