You can use notebook where WiFi/BT module can be easy removed. Examples include: Toshiba U925t Ultrabook, most (if not all) HP contemporary notebooks (just to mention few). IMO most of the contemporary notebooks use the same interface for WiFi/BT module which mean you can remove it on most of them. Just for the record for most of notebooks removing this module mean you need to disassemble it in some degree.
Combining this hardware with MS Windows bitlocker (for encrypted filesystem) and encrypted container based on Veracrypt or PGP disk as second level can do what you want. If you are not fan of MS (almost) any Linux distribution have disk encryption for entire disk and can be combined also with Veracrypt/PGP
Here is a image how this module looks like:
