Your options are limited:
1.) PolexPete and others have ruled out the Zodiac if I recall correctly. Getting hands and the movement to fit is too challenging.
2.) ETA 2836 with GMT module. ( I don't care what anyone says these are ALL ASIAN ETA's, at a minimum the module is)
3.) DG3804. The best Budget GMT movement out there. 21.6 bph, correct hand stack for 1675, and the 'newer' version date wheels line up with GEN Rolex Dials. Also, it fit in a GEN Case or Yuki with minimal modification to a Stilty retaining ring. (Yuki adapter would probably work also).
4.) A21J (multi-vendor) with "Fixed" 24hr running at half speed. (Technically most correct to the 1575-GMT as the GMT is NOT independently settable)
5.) GENUINE 1575-GMT ($1500 average for a well running/serviced version)
*6.) Convert a PT/Josh 1655 Explorer II
Personally, if budget is driving option 3 is pretty good with a GEN SPEC case or option 6.