Sorry, I know you can't really offer any advice that personal without seeing me, I just need to remember that In response to your questions:

I think I can manage at least trying to increase my mileage. Considering I feel no pain when actually running, I'm a little more worried about doing damage that might affect me post-run, as during the run my foot feels fine.

I've been increasing my distances and run frequencies over the past 2-3 months and running in the VFFs overall for about 8-9 months. I've done 21km in the VFFs once several weeks ago and felt better than I thought I would, with very little calf soreness and no foot problems whatsoever. Since then I've done between 14 and 18km runs in them, all of them feeling totally fine except that last 18km being the toughest on my legs (I suspect because of the amount of running I had already been doing prior to this that same day).

Haven't weighed myself in a while, but normally from memory weigh in anywhere between 43kg and 47kg, 5'4 in height.

I overpronate and used to have knee problems (pain, leg buckling under me when going up or down stairs sometimes because of sharp knee pain) until I started running, but then started having shin splints in my regular shoes, which is why I decided to try something else. So far haven't had any injuries other than this foot thing in the VFFs, no more knee pain or shin splints, but my legs are still built weirdly.

Regarding strength when running barefoot - I don't run totally barefoot because there's often glass and such in the roads here so I've been running in Vibram Bikilas. I'm not sure how to tell if I'm strong enough, but so far except for this weird foot thing that came about while I wasn't even running I haven't had any injuries.

I'm pretty fit for the average person, but not elite and don't run competitively. Run 5km in ~23 minutes, so nothing pro.

Hmm, maybe it isn't Wikipedia reference-linkcuboid syndrome...Taping did make it better, I don't have pain anywhere else and manipulation did provide relief but I can't remember twisting the foot. When the pain was sharp I did tend to kind of instinctively try to twist my foot in and land on the inside part (overponate on purpose) because that hurt less than pressing down on the edge. I think the reason it hurts me on the heel instead of the toe is because I still have to roll through the step. Right now the pain is mostly when the weight shifts around that area where the pain is, so rolling from heel to toe when walking. If I step on my toe there's no rolling and no pain. That's just what I noticed, not sure if this is really the reason.

Anyway, I guess I just have to see how it feels and be careful :S