Vacuum pump to decrease boiling temp

Has anyone ever experimented with applying a vacuum (using a pump or aspirator) to their boiling kettle to accelerate the process of reducing the runnings from an all-grain sparge down to the final boil volume? Obviously you wouldn't want the lower boiling temp during the actual boiling because of lower effective sterilization and hop utilization concerns. I imagine it could considerably cut down the time and gas usage it takes takes for example, to reduce 6.5gal of pre-boil gravity 1.060 wort to 5.5gal of 1.075 without any significant caramelization.

Of course, your boiling pot would need to be sturdy enough to withstand the vacuum, and a some sort of gasketed lid would need to be fashioned.

a small fan blowing at the surface of the wort works wonders for increasing boil-off rate.

Remember that steam generates pressure, pretty quickly, so your vacuum pump would have to be able to maintain a vacuum even as all the steam was being generated, so it would have to be constantly sucking steam out. I would guess you would need a pretty beefy vacuum pump that could stand to be pumping lots of steam, and probably wouldn't be able to maintain much of a vacuum, resulting in less of a change of boiling temp.

I would expect it to cost a small fortune, and the benefits are questionable.
You just mentioned boiling 6.5g down to 5.5g, well, for most of us, boiling off a gallon takes an hour or so, which is how long we have to boil for the hop schedule anyway, so where's the gain? If you were trying to brew some HUGE beer where you needed to boil many gallons of wort off (the samichlaus clone comes to mind... ) then maybe, but even then I think the caramelization and whatnot from the long boil is part of the style anyway.

Sounds like a very expensive and difficult solution looking for a problem.