As an owner of a Grob 109B with a VW engine and an 8.33 avionics fit + FLARM, I've been reading these replies with interest. I love the aircraft and it is a great tourer too (mine's been to the south of France and back) but it's one failing is that it is relatively underpowered for its weight which can limit where you can get out of (not into with those great airbrakes!). At Aero in Friedrichshafen this year there was a G109B with a Rotax 912 conversion. It looked interesting (I have pics if anyone wants to see them?) and makes the 'cute' G109 look much more purposeful, but it has yet to fly and with a price tag of circa €30K to convert, it seems that take up will be slow. Maybe if the MOD do go down this route it'll help bring the price down for us civvie owners?
In the meantime, we'll just keep trying to do what we can unofficially to fly disgruntled Cadets and stop them discovering street corners etc...