in theory you could make a mod that reduces the cost to produce all upgrades to 0 however i think you would still be limited to one per turn

Thanks for the replies folks

Oh well, the endless cycle of building upgrades is a large part of why I stopped playing GC II.  Nothing has really changed in III, I got a fair way into my first game then had to stop.  I'll not be starting another.  It seems a bit of a shame to me that Stardock had the opportunity to address many of II's shortcomings but in essence have produced exactly the same game; Infinite Building Upgrade Simulator...III.