I am not sure about the areas you live, but I still can find the VF-25 models (or almost any Bandai models) pretty easily.
For the models, they don't attach the armors and super parts only... Sometimes you need to swap parts. Therefore you may need to buy a separate unit if you want a plain VF-25 to display. They are all from Bandai.
BTW, if you are interested, the VF-25F w/ Tornado part has just released for a couple of weeks.
For Armored VF-25, you can find the 25F and 25S sets. For Super VF-25, you can find VF-25F and VF-25S sets as well, and also there is the Super Parts sold separately for your VF-25G and RVF-25.