Giving credit where credit is due: Sparks' proposal to mechanize the combat support companies in parachute battalions doesn't seem outlandish to me. Some airborne forces have light tracked armor but the US makes do with up-armored Hummers.

I believe Sparks' idea was that the company's vehicles could continue to be used as platforms for crew served weapons (like the Hummers are now), transport one of the rifle companies, or serve as something like a cav troop of sorts for the battalion commander. I may not be understanding that exactly right, but I think that's more or less what he envisioned.

So, assuming that the M113 isn't the best option for that role, what light tracked armor would be suitable that can be airdropped? The German Weisel? Something else?

There are some cav types on this board who should have some good ideas. I never experienced anything heavier than leather personel carriers or the old 1/4 ton jeeps, so I have no idea what can or can't be airdropped and what the logistical problems are.