Make a water-cooled undershirt like those for astronauts and get one of those fan attachments for baseball caps. (Slightly wacky suggestion but this is hacker news after all.)
That's a crazy idea. Have an upvote :-)
Another silly option is wear multiple layered suits like it is the early 20th Century again. While all the layers will contribute to overheating and the sweating problem, a part of the reason for the layers in the first place (especially in the early 20th Century before modern air conditioning) was to keep sweat to less visible layers. Make sure you stay hydrated, of course. Maybe go Steampunk with it and have fun picking a weird style all your own.
Yep, that's a pretty silly option. It's not the cosmetics of the situation that concern me, it's the physical discomfort.