Weighted adjustment for relative Elo I was looking at my biggest upsets the other day and realized that the result was unsatisfying.  Most of them were 500-600 point upsets when I was still really low rated (i.e. 800 beating a 1300), while the upsets I consider the greatest have been the 150-200 point ones scored as an A player or expert.  Similarly, it would be a much bigger upset if a 2650 were to beat Levon Aronian than it is for a 1500 to beat a master.  It seems like the higher ratings go, the greater the points matter - a 100 point difference matters a lot more the higher up you go.

Can anyone come up with a weighted or logarithmic way of representing Elo ratings on some sort of scale so that this is accurately represented and players can be compared in a consistent manner, or does such a scale already exist?
I think the phenomenon that you're describing is due to variability in play at lower levels.  Elo is defined based upon the statistical likelihood that one player will beat the other.  

Here is the exact formula to get the expected score for a player (rating = Ra) vs an opponent (rating = Rb):


This means that an 800 player is theoretically as likely to beat a 1000 player as a 2200 player is to beat a 2400 player.

Obviously this is not the case because at the lower levels, there is a much higher variance in the results.  This difference is captured quite well in the Glicko Rating System.  Basically, a player has a rating as well as a ratings deviation (RD) which represents how well established a player's rating is.  So in your case when you were rated 800, most likely you were closer to 1100 or 1200 strength but your rating had not yet caught up to your strength.  It is one of the fundamental flaws in all rating systems that the rating always lags the strength.  If the USCF used the Glicko system, then these early wins would have resulted in a far greater rating jump than actually happened, and your opponent would also have lost fewer points.  

So to summarize, while the rating systems are not perfect and your strength will frequently be above your rating, an 800 beating a 1000 and a 2600 beating a 2800 are both equally likely from a purely mathematical standpoint.