Well apart from cutting back all the range ability bonuses that are gained from life support techs, you may want to consider seriously limiting the range of life support modules that are available, making them bulkier, more expensive, etc.  But also, add a free tech (0 research cost) to each race which negatively modifies range by a fairly hefty amount.

I'm glad I hit this post.  I was hoping that I could put negative bonuses in the starting techs, instead of mucking around in the race configuration files.