Interesting question.

First, there's plenty of HV rated servos and most ignitions made today (not counting your DA 50 which has been around a while) will take a straight 2S LiPo.

Now back to your issue. You're talking about a "civilian plane", thats open ended, what sort of plane is it and what type of flying are you planning? Nothing running a 50cc engine really needs the expense, complexity, or weight of a SmartFly board IMO but they are nice.

In reality, you probably should have been suggested to use A123 batteries with a simple and inexpensive voltage drop down for your ignition. WrongWay RC sells voltage drops for both Lipo (dual diode) and A123 (single diode) inline voltage drops that work perfectly on ignition systems that can't take HV. That won't help you with your servos though, and you haven't mentioned which servos you purchased.

HV setups have their place, but unless you're doing cutting edge 3D on a plane with large surfaces, and are in the upper 10 percent of pilot ability (i'm not by far! ), its really not necessary.