I went and improved Dei's Halberdier standing map sprite: [link removed, see below]
My issue with the old standing map sprite was that it was about 3 pixels shorter than the moving map sprite in addition to having a different shield size. It was also leaning to the left unnaturally and seemed to be missing the top of its head. I corrected the left lean, corrected the missing top of the head, made the sprite 2 pixels taller (which is consistent with differences between existing standing and moving map sprites), fixed the size of the shield, and made the lance bigger.
Also the moving map sprite (particularly the walking frames) is still too tall; I might work on fixing that later.
EDIT: Here's slightly updated standing map sprite: http://i.imgur.com/RurUO04.png
And here's an improved moving map sprite: http://i.imgur.com/0OLzrli.png
The standing map sprite grew taller yet another pixel; this time it's the same height as the stationary moving map sprite. The new height compares more favorably to other infantry units, since the halberdier has a pointy helmet. The moving map sprite got a slightly different stance, and its first frame has the lance raised above the head instead of held to the side. The downward-facing and upward-facing moving map sprites lost one pixel in height; they're now the same height as the side-facing moving map sprite. They're still 1 pixel taller than the standing map sprites, but the difference is small enough that it looks acceptable.