Two issues I can see with this: first, your queueing order could get messed up if you order big ticket items and then inexpensive ones. Say you add a 3000money capship to your queue, and then add a couple 400money frigates. You'll raise the cash for the second first - do they get built first and delay the capship, or does the money sit unused until the capship is saved up for? That's a decision the player might wish to have some immediate control over.

The second,and bigger problem, is that needs can change in the middle of a big battle, and you'd have to "de-spend" your money so you could focus it on other things. For example, you're trying to conquer Empire A just beyond Chokepoint 1, and suddenly at Chokepoint 2, Empire B launches an attack that really needs some frigate defense. So transferring your queued construction to the facilities that are closest to Checkpoint 2 is required, otherwise you'll get maimed there.

If you have to leapfrog between frigate construction screens and research screens to remember the order that you had requested your build/queue in and reverse it all, it would be really distracting. So maybe a series of decals across the screen bottom, each representing the next thing that will be built/researched as soon as you raise the money, would be a good way to handle rapid cancellation of build queue orders. Clicking the "cancel" option on any decal would cancel it and any further build orders so you could reallocate your construction queue elsewhere.

Anything that influences the GUI is generally a pretty big feature change, so this likely isn't easy to do.

-- Retro