Bushy, i think you are about double what a PT6 overhaul would really cost, unless you don't look after the engine.
I believe the F406 has pretty reasonable running costs and you can pick up a late 80's/early 90s model for under $US900K.
Don't know much about to T-1040, there is not much info/experience around on running costs.
dasjab, you'll find you can get early to mid 90's 208s quite reasonably priced. The reason financing is usually so good on a 208 is that they hols their value extremely well.
I can't say this for F406, but it does bring the price down quickly if you can't afford to buy a new one!
Bring on these baby bizjets, they will change the scene of charter (hopefully).
The PA31 is a dead and buried machine and operators who hang on to them like they are the world's greatest aircraft will get left behind as governments and other regular charter clients demand turbines and take their business elsewhere.
GA in this country seems to be scared of the potential costs of turbines. You don't get this fear in the US or europe and it works well over there.
Pax love the turbines cause they are generally quicker for them than pistons to get from A to B(except for the van), and that is why they are flying in the first place!