Some screenshots of my female TF2 Heavy character mod (to this point, still quite a bit to do). If you're interested in testing it out in-game for me (or doing the voicework!), see my journal here: [link]
Some design thumbnails for the different classes: [link]
I doubt it. One of Valve's spokespeople actually said that they would "love to [make female counterparts] but it isn't likely to happen". They said this on the grounds that doing so would require new models for everything besides weapons to avoid clipping (try putting a sweater on a femscout and you'll see what they mean). This would require lots of time and money even for seemingly minor changes, especially with the 100+ items TF2 has at this point.
I'd hit it.
do a female sniper next.