I released a new version of SoldatUT today, as part of my ongoing work on Marshmallow Duel : Mowbray's Revenge.
If you haven't heard, SoldatUT is a 2D mod for UT2004 that brings all the default gametypes to a sidescrolling play field. The latest version includes 2D onslaught play with vehicles, as well as fixed weapons, bugfixes and new maps.
You can head over to the files page on the MD:MR site to download the mod and find links to maps for it.