If you only have the USB jack on the machine you are considering, you will either need a standalone USB to MIDI Host device or a computer of some kind. Yes, some keyboards offer the USB Host functionality, but I am not privy to the exact models that do.
I cannot imagine that a product would not be available in a certain country, as you can always order internationally to get what you need (unless no company sells in your country).
I would caution against the Kurzweil SP1 as an option, as while it does have the 5-pin MIDI jack that allows for MIDI setups, it has problems with the MIDI Solutions MIDI Thru devices that they sell. The Kurzweil SP1 (and other Kurzweil products) are not able to power these devices and you will need to buy the power adapter directly frmo MIDI Solutions (who are based in Canada). I have an SP1 and learned the hard way before a gig that they do not pwoer the MIDI Thru boxes without the addition of the Power Adapter device (which cost me $50 USD).
This may sound like a rant against the Kurzweil SP1 and I suppose that it could be considered as such. The piano sounds on it are terrible (that is why I wanted to MIDI different keyboards to it), but the EP and Strings are pretty good. The action is great (in my opinion). What I really liked about the SP1 was the fact that each 'section' (Piano Section, EP Section, String Section, Other Sounds Section) had individual volume controls right on the front face of the keyboard. That allowed for 'on the fly' volume changes without having to dive into menus to set volumes for the different parts. It is a lightweight board as well and again, I liked the action.
In correspondence with Kurzweil, I got the usual 'runaround' about the product. They tried to tell me that I needed a flagship model from them instead of trying to find solutions for the product I already had. They also said that it was a beginner/student model, while they are promoting it on their website as a professional model; this is misleading.
If you are looking to simply play the sounds from an 88-key keybed, then maybe a controller is the way to go. If you plan on layering the different sounds together between the two, then you still have many options, many of them in the $500 - $1500 range.
Grace,
Harry