We are something of an international company. We have offices in the US and Ukraine. Our funding comes from Runa Capital, which is Russian. I am based in Houston, TX. :)
As far as engineers and such, we are on both sides of the globe, US and Eastern EU, so that we can cover all times zones well.
Not sure about adding a support phone number. I've always had bad experiences when providing that as another option for support, especially in today's hyper connect world. We find that most our users (>12k) prefer the forums, support tickets and Twitter and Facebook.
I do like your idea for a messaging system. I've actually been considering Olarq. I'll most definitely make sure that we talk about this. :)
Thanks for the suggestions!