@Bartamos: the last time I built a system from parts like that, it was about $1400. Cheaper than a custom, drop-in solution from a big name, but more than the universal electric kits.
I agree that it is a perfectly fine solution that has worked for a lot of years and I would not discourage someone from building one of those if that was the direction they wanted to go.
I suspect it could be done a bit cheaper now because the evaporator/heator core/fan unit that the electric kits use are available by themselves for pretty cheap.
