One idea which would be interesting is airborn drones : you know, those cheap flier drones which are remote controlled?
I figure they might be handy in scouting tasks (monster attacks on towns) as well as just in general, as an agile, flying, flexible unit to look around, and possibly even grab light objects out of reach. The flying alone would be useful for scouting, making it immune to all sorts of critters assuming its in the air, allowing it to imperviously peek around and scout where people would be in more danger
Also, maybe as a later game option, a heavier, armored drone, with minebea SMG, or even modified berreta installed?
I know flying armor is a long way out, but getting some kind of airborn capability early on would be very useful, EVEN if the first one is extremely fragile, and without weapons. Plus, if you gave it the ability to hold 3 weight units, it could even be used as a sort of bomber with grenades.
And honestly, such units don't sound too far outside the scope of xcoms funding, tech level, and military regulations to access.