I think we have a more complex problem. No one is being represented on the basis of paying taxes (disproportionate or otherwise). Representation today is either an ideological allegiance (progressives on the left and conservatives on the right), a small scattering of well-meaning moderates who flounder about in an absence of clear principles, and all the rest are bought and paid for by special interests. That is the same as NOT representing anyone.
Not so strangely, it is the people who are paying the most who are the least represented (the most abused with regulation and confiscation). It is those who pay the least that are the most represented in today's world (AIG, welfare bums, agro-business, dictators receiving foreign aid, etc.)
And, in my thinking, representation is really only a checks and balances kind of thing to slow down any trend towards statism since government derives its moral basis from adhering to laws drawn strictly from individual rights - and not from the fact that the leaders were elected.