After some serious clicking, I've finished updating
Birmingham and the surrounding West Midlands metropolitan area. It contains an astonishing
15,000 buildings, and that's not even including satellite towns outside the metro area. Rail lines, train graphics, and timetables in the West Midlands have also been updated, as well as Herefordshire & Worcestershire.
Here's the Birmingham area looks at the widest zoom level. For context, Redditch is in the bottom left, Birmingham Airport is near the bottom right, and Wolverhampton is in the top middle.

(Larger version
here)
And here are some
new/updated West Midlands/London Midland-liveried trains from the area. This includes the West Midlands Metro trams, whose network is newly-added to the map:

In addition to rail & cities, the motorway network is also present. You can see them in this minimap shot - you can probably also spot how some of the outlying towns haven't been rebuilt yet.

One more screenshot showing stations in the centre of Birmingham

A fuller list of changes:
Trains- Class 170: London Midland livery updated and West Midlands Railway livery added
- Class 172: LM livery updated and WM livery (orange) added
- Class 323: LM livery updated and WM livery added
- Urbos 3 tram (West Midlands Metro) added
Rail network- Added West Midlands metro tram network. It goes underground in central Birmingham and Wolverhampton because of the density.
- Revised CrossCity timetable (including Bromsgrove additions)
- Revised Snow Hill lines timetable
- Many lines branching out from Birmingham were re-aligned for greater accuracy, including freight-only lines
Cities & towns etc- All West Midlands metropolitan boroughs rebuilt (Birmingham, Solihull, Sandwell, Dudley, Walsall, Wolverhampton)
- All of Herefordshire & Worcestershire also rebuilt (Worcester, Malvern, Hereford, Ross-on-Wye, Leominster, Bromsgrove, Droitwich, Kidderminster, Redditch)
- Rivers Wye, Avon & Severn substantially rebuilt in this area
Bus network- Worcester buses to: Evesham, Great Malvern, Bromyard
- Gloucester buses to: Hereford, Newent
- Hereford buses to: Ledbury, Leominster
No Birmingham area buses yet.
The savegame and pak folder can be downloaded at
this link. As ever you will need a legacy Experimental exe to run this map.