This is an interesting, if meaningless, exercise to while away the time. As someone has already more or less suggested, buy the set, watch it for a while and, if it seems annoyingly low, buy the stand. I'd amend that by saying, instead of the stand, buy or fabricate something that raises the set about 10" off the floor. Actually, Sony and its dealers were giving the stand away for free with the KP-46WT500 as a promotion. That may still be available. You've got options.
I recently read somewhere, and I forget where at the moment--but it was as authoritative as this nonsense gets, that the ideal TV viewing height for screen center is 2 degrees *below* eye level. Now, the center of the Sony KP-46WT500's screen (without stand) is 27.6" off the floor (give or take). Eye level for your average adult type sitting on your typical cushy living room furniture is somewhere (depending on the cush and the stature of the individual--your mileage may vary) between, say, 34" and 36". Right away, I see that you're either a really short fella or you're sitting on a futon since you say the screen center is only 4" below your eye level.
Anyway, if you're sitting 10' away from the set and your eye level is about 32" (27.55" + 4.2" = 31.75"), that's about "ideal" and screen center is, for you, about 2 degrees below eye level. Congratulations! If, on the other hand, you're only 8 1/2' from the screen (which is about right IMHO for the screen's height), at 2 degrees, the drop is 3.6" which is still reasonable. Only if you're mistaken about your eye level or the height you've assumed for screen center should it be suggested that the screen is too low. Still, if you like it that way.....
The downside is that people who are standing will see much diminished display brightness. The vertical viewing angle for typical RPTV's is extremely narrow.