I think there's a ton of hurdles this will have to jump before it makes it into certificated aircraft. Homebuilders may see it fairly soon, but I'd be suprised (shocked, actually) to see it in widespread use in general aviation within 20 years. I say this for a number of reasons;
Beauracray. Getting FAA certification on ANYTHING is a formidable task. Most piston-powered aircraft to this day rely on fixed timing magneto-ignition. Why? Because designing and certifying an electronic ignition system with fail-safe backup is very dificult. Such products are only now coming to market.
Fear Of The New. Closely related to beauracracy. The Beech Starship is an excellent example here. The FAA had never seen an all-composite airplane before, so it slapped a bunch of requirements onto the Starship that ultimately played a very large role in making the Starship a monumental flop. The losses from that project nearly drove Beechcraft of of business. In the case of GPS, the FAA was driven by external forces to fast-track acceptance of GPS-based navigation. I don't see any external forces exerting pressure on the FAA to accept HITS. NASA's track record on getting the FAA to change is unfortunately very poor.
Cost. It's been said the best way to make a small fortune in aviation is to start with a large one. I am extreamly skeptical of a HITS panel costing the same as a current panel, unless they are refering to a current EFIS (Electronic Flight Instrumentation System) panel, which starts at around $100,000. BTW, aviation has had GPS navigation for years as well, and LORAN before that. HITS is much more than GPS navigation.
Safety. The one LCD display panel creates mulitple single failure points that can bring down your entire system. The panel itself could fail. An electrical failure would leave you staring at a blank screen. Sure hate to have that thing BSOD on you in the middle of an instrument approach into Colorado Springs. Airliners have mostly independant power and sensors for pilot and co-pilot, plus a third set of, you guessed it, the old round instruments for backup. Small GA aircraft can't afford the weight penalty. The use of mulitple systems (electrical, vacuum, pitot-static) yields a measure of safety in the current designs. Even with total electrical failure in the clouds, I've still got altitude, airspeed, heading (compass) and usually the artificial horizon powered from a vacuum pump on the engine. Plenty enough to keep me upright while I dig out my handheld and get vectored to sunny skies. And I have yet to see any display that is easy to read in direct sunlight.
No Benefit. I don't see a big benefit to HITS. Navigating just isn't that hard. I certainly don't find the gages cumbersome. In actuality, airplanes rarely crash due to navigational errors. Most GA crashes are loss of control in instrument conditions (in the clouds, ala JFK, Jr.) and running out of gas, followed closely by gross errors in judgement (buzzing, performing acrobatics in aircraft not certified for them, etc). The navigation-related crashes that do occur are usually preceeded by pilot error in setting up the equipment in the first place. I don't see how HITS will fix, or even help alieviate the problem of pilot error.
I'm not as resistant to change as I sound. The first time I used an HSI (navigation information superimposed on a heading indicator) I was hooked. GPS offers low-cost instrument approaches into airports that never could have afforded ground-base approach equipment. But merely changing the way navigation information is presented in order to make it look "hi-tech" is pointless.
Why did I flip? I got tired of coming up with last minute desparate solutions to impossible problems created by other fucking people.