[PvK]

Foundations mod was a bit more like that, because you started out with Chemical Thrusters (markedly weaker and shorter-ranged than Ion Engines), and that was also before I added the Efficient Engines in one of the early Proportions patches. Increasing the supply use of effcient engines to closer to regular engines would help achieve the effect you're looking for. You could also reduce the supply capacity of all engines.

Also, a major element speeding expansion beyond the design's intent is the ability to build colony ships using space yard ships, so you can build the colonizers at the frontier.

One very spiffy idea (of SJ's, or Geo's maybe, I don't remember - sorry) was to run a "turn blitz" Proportions game on PBW, where there is a automatic turn every hour or so, so players focus on long-term actions, leave most details to the ministers, and get to see a lot of long-term development. This could be done either for the whole game, or just to advance it to a certain point, say 500 turns, and then slow down to a normal rate, in order to play with a more advanced state.

PvK