[greendestiny]

For any common pairs of applications that means n/2 tabs on average to switch back and forth.

[abstractbill]

No, because you would manually shuffle common pairs of applications to be next to each other.

[greendestiny]

It would need to swap the common pairs on use. Which is basically this guys scheme except you manually define the pairs.

Then again on windows you can alt-shift-tab, so that pretty much takes care of that anyway, if could just have the programs in consistent order.