Great info everyone, I appreciate it (as well as the examples). I think you're right that I need to get over my inhibition and just do it while I still have the chance. I like the suggestion of draping a nice blanket over the car seat or bouncy seat to make a better backdrop.
I gave it a go the other day. This is 8x10 HP5+ rated at 800 and pushed two stops. I also shot it on 8x10 Astia, but it was just too slow for the lighting.