Yes, you heard right! I've managed to fix that awful trim problem. I've added a bunch of other fixes & enhancements too:

Note: These modifications do not require the V-One gauge to be installed.
Any user with a modified flight model will need to adjust the CG offset for proper auto elevator trim.

Now available in the Avsim Libray, search for:
Boeing 727-100/200 Various Fixes

- Airspeed Indicator Enhancement
- ADI & Flight Director Corrections
- A/P Enhancement for Flight Director
- Radar Altimeter Fix
- TAT Display toggle via DME Indicators
- Trim Sensitivity Fix
- Auto Setting of Altimeter Alert & Elevator Trim
- GPWS Switch Fixed
- NAV/GPS toggle via Marker Beacon Sensitivity Switch

Many thanks to Markoz for you time and testing  ;)