objects that scale with text

I think you can already do what youre asking about:

Flow text into a frame
If the text doesn't fill the frame completely use Text tool to add more text and keep writing until you've filled it and then some more (you won't be able to see the last few words you'd written because they are out of the frame)
Now select the frame object and resize it -> as the frame grows the missing text appears

Is this what you wanted?

Nope. Open office draw has this feature, so that is the best way to describe it. Do this to see what I'm talking about:

* oodraw
* click on the flowchart icon to place one of those objects (mine looks like a hexagon, but this may not be the default)
* place it somewhere by clicking for the first corner and dragging to the second
* right click in this object and select "Text..."
* click "resize shape to fit text" and then "OK"
* click on the text icon at the bottom of the window
* start typing some text and notice that the shape changes size with the text

I though maybe just flowchart shapes worked with this in oodraw, but it looks like all of the builtin shapes seem to have this option (but user-defined polygons do not).

Right now it seems like oodraw is better at flow-charting, but with a few more features in inkscape, it would be quite usable for flow-charting and be a lot more general.

Yes I thought thats what you meant. So what you want basically is to have the process automated from the reverse angle, in Inkscape the text is the automated object that molds itself while the frame doesn't change. If you want the frame to adjust to the text you have to manually resize the frame (the text will follow), and you'd like that frame to resize automatically as you type.