Yeah people are reporting the issue. Apparently it has to do with dual head video cards, particularly the NVidia ones and multi-monitor setups. The game reads the dxdiag.txt to determine your possible settings, but it sometimes screws up when reporting. The workaround is to disable all monitors and video cards but the one you'll be using, create a dxdiag.txt manually, and then save it as read only.
I tried the game on my 16:10 cab monitor and it worked, so I don't think this is an aspect ratio thing, I think it's a reporting thing.
Oh btw... they've already released a tool to encrypt/decrypt the coalsecd.ini which stores a lot of settings, including viewport and framerate settings, so there might be a fix there as well.
All we are waiting on in terms of mods is a .xxx file packer. The old unpacker for the consoles works, but the encrypted files have reverse endingness, so you can't pack mods back up and you can't edit the textures yet. But that is a simple enough fix.