One possible solution is to use custom SQL queries to query the data dump at data.stackexchange.com and calculate only upvotes. However, this is possible only after we graduate, which is when the data dumps become available.
In the meantime, you can use the API and run it as often as you'd like (upto 300 calls/day) from the comfort of your Frontend. It only needs a minor modification to Sjoerd's example here (specifically, get the top 20 users for this site instead of a particular tag as in the example)
However, re: your feature request, I do not think this is a feature worth an SE developer's time. It's a very specific request for only this site, solely to stick to old habits, and will not enhance the experience of the site for most people. Hence, I vote no.