Interesting to think about it from this perspective. Just off the top, I wonder if we could have a second level. Then each "Advocate" (just picking a word) that represents 10K people would then be the constituency for the representative. This is a model like the Rep is the CEO and the Advocates are the C suite. The Advocates never go to DC or the state capital, then only remain local. Then to make things simpler and cleaner, outlaw lobbying at the Rep level and make the Rep elected by most votes among the Advocates. Now to get a quorum on the Rep or an issue, lobbyists have to try to convince a majority of the Advocates. Hopefully this increases the cost and decreases the payoff. It could also be that the role of the representative is to just help with the negotiations and wrangling for the bills but doesn't actually get to vote. The act as a Super-Advocate based on the position of the majority of their Advocates and in the end, the must cast their vote on a bill based on a sub-vote of their advocates.

Don't take the above too seriously, I'm sure there are holes. Just a thought experiment in my brain right now.