Guys, the brick limit is not an issue, unless I missed something.

Also brick lag is caused by exposed surfaces. Try building, say, a tower made out of ramp bricks. Then build a tower out of regular bricks with the same amount of bricks, and compare the lag you get from both.
A problem with the idea is due to how the bricks work. Any surface on a brick that is hidden by another brick placed directly beside it is not rendered. So, stacking several red bricks to make a pillar will omit rendering of the unused "Stud" surfaces and the "Bottom" surfaces that are being sandwiched in the pillar and thus not seen anyways. But, if you've got a good eye for it, repainting those bricks with Trans paint will cause those previously hidden surfaces to render. That's part of the reason why completely Trans builds can sometimes lag obscenely.
That bit of code is pretty ingenious really, but it's also why this idea could be difficult. For this to work without causing the build to actually lag More then before, you'd need to save the un-rendered brick faces, otherwise all the hidden and un-rendered faces will basically appear and then you might as well paint your build trans because that's the kind of lag you'll get.