If you run a TF2 Arena server, you may be interested in giving this map a shot.
I've modified ctf_mach4 into the Arena game mode and have given the outdoor environment a visual makeover. The map includes many changes to fit the Arena play style. The middle area is now larger. Players can now get up out of the previous flag area pit easily. A spawn room has been eliminated, and the sniper deck is accessible to all from outside the base. There is more cover outside. The sky is much, much higher than in the CTF version. This is a bit different than other Arena maps, because I've opted to have a decent amount of health packs around the map. There are two small ones in the middle (one on the tower, one on the stump), one small in each sewer entrance, and a medium pack on the previous flag stands to encourage use of the bases.
Screenshots:
http://www.vilepickle.com/map/screens/tf2_arena_mach/Download:
http://www.vilepickle.com/map/arena_mach.7z (7zip, 7.3mb)
http://www.vilepickle.com/map/arena_mach.zip (zip, 10.5mb)
http://www.vilepickle.com/map/arena_mach.bsp.bz2 (bz2, for server admins)
This is a version 1.0 release. I did private beta testing to stomp any bugs that came in the conversion process. If you do find anything major though, let me know.
Enjoy the new alpine environment!