Surface Pro 4 is WiFi only. You can connect it to your phone via WiFi.
How about the Samsung Tabpro S2, due to be released at the end of the month?
http://www.theverge.com/circuitbreaker/2017/2/9/14558220/galaxy-tabpro-s-2-specs-leak
Compared to the i7 Surface Pros, it falls a little short (i5, 4GB RAM, 128GB SSD). But it comes in 4 versions, 2 of which are LTE.