> The calculator program would generate a description - perhaps using XML -
> that defines the initial size of the window, the placement of all the
> buttons, labels, pull-down menus, etc, as well as callbacks for each
> button for which it's interested.
...
> it would work similar to some of the web 2.0 applications out there,
> but without all the client-side javascript.
What would be the point? The main problem with remote desktop
applications is user interface latency, which client side javascript
neatly eliminates for simple operations - such as calculator operations.
HTML/JavaScript is in many ways the better than running desktop
applications remotely. Which is, incidentally the reason why only
a vocal minority cares about remote X these days.
The only remaining reasonable usecase for remote desktop is user support.