If a person is studying both japanese and chinese, is it possible for them to do both with the same account? If not it would be really great to have that functionality.

That would definitely be a plus, seeing that this is a pay service. I don't plan on studying Japanese in the near future, but I might someday and I'd hope I wouldn't need another account.

But then, would the practice page have to be adjusted to set for language? It could get confusing if you are getting reviews for both at the same time.

Looks like you can change it in your account settings for now.

Change it over and practice one for a while, change back and continue with the other.

As for paying for two accounts, I would be very surprised if that was the case. We pay for the awesome service and ideas behind Skritter, not per language, lesson, or word, right?

Yes, I practice both Japanese and Chinese characters with my account. To switch between languages, just change the language settings in the "Account" page. It will save all your progress with the other language.

Levi and Thomas are both correct: when we do launch the paid version of Japanese in January, there will be one subscription to rule them all (to quote the lord of the rings). If you would like to learn both Japanese and Chinese at the same time (prayers be with you), go for it! As Levi mentioned, you will have to switch between the two languages, aka, you won't be able to intermingle Chinese and Japanese practice, but the other language will always only be a click or so away.

I also study both languages, although I'm concentrating my efforts on Chinese at the moment. Am I rightin thinking that certain characters, identical in both languages,have a different stroke order? For example guo3/kuni (country)

Yep. We do keep separate copies of the stroke orders for all characters, so you'll get different stroke order feedback depending on what language you're studying. For 国 in particular, in Japanese, the middle vertical line can be the fourth stroke, but in Chinese it's the fifth.

Yes,it gets a little confusing. Does anybody know of any list which shows the most common variations?

Here's a PDF I found with some rules about stroke order differences between Chinese and Japanese:
http://www.jvgruat.com/Chine/strokes.pdf

This isn't for stroke order, but here's some charts with differences in similar characters between languages:
http://en.wikipedia.org/wiki/Han_unification#Examples_of_language_dependent_characters
(Doesn't work in Chrome, maybe others; try in Firefox if they all look the same.)

That's useful. Thanks