I would like a four slot version, though my two slot seems to work fine charging my phone with a couple of 18650's. I haven't tried charging a laptop with the Xtar, I'm sure that wouldn't work quite so well. So a four cell version would definitely be welcome. One thing I have always wanted to see, and no one has really made a decent version of, is a charger that will accept CR123A primaries. I haven't tried this with the Xtar and not sure if it would ruin the warranty/charger. But in emergency situations, for those of us that have a stockpile of CR123A's it could be a literal lifesaver.
And a version that will take AA's would be cool too. Like a 16 cell version or something like that. With enough alkaline cells you could charge a phone. Rayovac tried that with a 4 cell AA. I had one and it didn't work very well. But with alkaline chemistry, I think that the more you divide the current draw between the batteries and lower that, while having that voltage advantage, would make it feasible.
