IIRC XTX is still being worked on. It's just that daTS has lost the contents to it by unlucky computer problems 2 times now. I do believe he has allowed Harv to help him with some of the things for XTX and I do also believe that XTX has some extra vehicles being added to it.
Anyways this looks amazing LKO. I think this will have a good place in TS: Ascendancy. (if I ever get the want to actually work on that and revise it some and stuff. lol. )
I have a few suggestions/requests on some things that would be nice to see though.
Buildings:-Car factory/Car workshop (would have some kind of garage like door to allow vehicles inside the building) *could also be used as a tech building
-Radio towers, Cellphone towers, etc. lol I know TS set in future but they are bound to have one of those around still.
-A Mall/shopping center like building
-typical buildings that would fit as a shopping outlet like area. (possibly be put next to each other to look like one big building that is split into different shops)
-A better waterfall dam (that possibly actually fits well with the shore spots unlike the current TS one)
-Another type of City like power supplier thing. Such as a civilian styled power plant?
-Parking lot Lights. (ya know the ones that have 4 lights on them and sit every so often in parking lots)
Others:-New trees if possible. my preference would be a temperate kind of trees that are more like the snow theater ones which are bunched up. Like the snow theater has 5 trees in a bunch on a single tile for the Tree#7 and a few others. This would allow for more realistic forests on temperate maps.
lol thats quite a bit. Of course its up to you if you want to do those as they are only suggestions from me.

Oh and I'm sure if I sat and thought about it I could come up with more if you want.