I just finished typing up an e-mail to my DM, since we were currently discussing this. I did some math which some might find handy, so the e-mail is included below

I used the original factor of Khorvaire being 5,000 miles across, by 1,750 miles up and down. these are rought figures that i garnered by quickly using the scale of course- but I think they're pretty accurate.
'On shrinking by 10, if you're still following that post- this is an interesting point:
"1. The maps are erroneously multiplied by 10 (according to Keith). So this would make Khorvaire 500 miles wide, not 5,000. That would make Khorvaire way too small in my opinion; the entire continent the size of France."
that does seem too small.... the entire continent being twice the width of wisconsin? Not even as far across as Texas? 1/10th scale would make it roughly 87,500 square miles (roughly).
That's almost exactly the size of Minnesota... now I admit I'm biased by my cars and planes, but it doesn't seem realistic that you could have that many seperate cultures, cities, terrains, etc. in the landmass of Minnesota...
Maybe just halving it? Halving it would make it 4,375,000 square miles.
Europe is 3,930,000 square miles for comparison, The U.S. is 3,718,695.
that still seems big... but more reasonable, what do you think?'