Now here's an idea...
Fakeisthenewreal, the same online presence who crunched the data to figure out the most- and least-densely-populated block groups, has redrawn the U.S. map into 50 equally-populated states:Unfortunately he didn't show how he did his calculations*, nor did he make available any more detailed maps showing exactly where the boundaries are. But it is kind of fun to play with maps this way.
* If you don't want to crawl through too much data, you could approximate things by creating clusters of eight and two-thirds congressional districts. Counting the District of Columbia as a congressional district to get 436 districts, you'd have eight remaining thirds of districts to distribute after you divide that total by 8 2/3. You could even things up well by tacking them onto the clusters in states with smaller districts**. The annoying thing there is that the boundaries of congressional districts are so gerrymandered in most states that they don't represent any coherent geographical concepts.
** Congressional districts represent an average of about 650,000 people each, but differ slightly from state to state, as each state has an integer number of representatives.