NASA has been working on HITS for years as part of their AGATE (Advanced General Aviation Transport Experiments) program, spurring several avionics manufacturers to incorporate the technology in their glass cockpit products. Some HITS implementations combine synthetic vision (graphical representation of the terrain drawn from database data) with a very easy to understand graphical format that makes instrument flying almost child's play.

Impact of Aviation Highway-in-the-sky Displays on Pilot Situation Awareness

Glass cockpits are slowing appearing in private planes like the Cirrus CR-22. They're still somewhat pricey but, as in most things electronic, the prices will probably come down in the next few years. The new systems incorporate solid state gyros, so their reliability should be much better than the old vacuum instruments, too.