But they have been "mass producing" mode A/C transponders for years and they are still approx £1200. I do realise that there will be many who can't afford even that, but I was trying to point out that if you look beyond Garmin/King you can halve the price of mode S (if you want to!). I'm currently building a Europa, and since I'll need a transponder to visit parents/inlaws in Jersey, I'm fitting mode S because I can see no point in paying £1200 now and £2000 in 2008.
The only thing that you can be certain of is that they will be cheaper a year after implementation!