How about something more simple?*
you're allowed to select up to say 5 constructions/researches in a queue.
However, (unless you adjust it or something), while the first research will obviously be as normal, the other researches in the queue will be extended - 10% for the first queued one, 20% for the second one, 30% for the third one, 40% for the last one (rounded UP).
constructions should be 20%, 40%, 60%, 80% respectively, again rounded up, to stop Terrans abusing it with production set as #1. we can apply the penalty before race bonuses as well / instead.
So, you'd get something like this:
Code:
Construction # Construction Time Left Total Time Status Action
Construction 1 Medium Factory 5 10 (building) [cancel]
Construction 2 Finance Center 14 14 (queued) [remove]
Construction 3 Finance Center 18 18 (queued) [remove]
...........
[remove all queued]
where [ ] is a clicky button
So basically, you can queue things up, but it gives you more time each time you queue something up. Alternatively, you can ignore the bottom 4 slots and just use the current one :-)
*after writing it all out, it's not so simple when I try and explain it.
edited: post consistancy in terms of numbers/%s