I actually have about a half dozen or so double-sized icons from this run sitting around on my hd. I will upload all of them when we have all the NPCs.

If I am using a game sprite to start with, I work at double-size and then reduce (and retouch) for the NPC icons. If I am starting with an Uatu icon, like I did for Penguinn and riddler, I start at normal size and there is no double size version. I am conidering when this is done making double-sized icons of the ones that don't have the larger size already.
I have another dc villain to offer today - Harley Quinn. I went with the classic look, but as with many of the other Gotham-related DC icons, I plan on doing an updated look as well (updated = New52).