Nicksouth,
You cannot go wrong with the P45+ (a classic DB and definitely good long exp system)... amazingly, it is still highly sought after (that is if pixel counting is not critical)!
With WA application, LF digital lenses are the best you can get for the application esp with large IC and no multi-factor added to your MF WA lenses. Longer focal application (IMHO), I have stuck with the DSLR - or MF/DSLR. I have done an aerial assignment once with my HR28 and HR35 on a Cambo WRS and works brilliantly well... I will be doing more.
Manual focusing in not an issue as I come from the humble beginning of Nikon F2 and 6x6 journalism era,
NOTE: certain DB do not graft well with technical camera when outside a "studio" environment - see Alpa website (Oct 2009 issue ?) - so do bear that in mind.
But for ease of use, nothing beats "auto focus" point and shoot with a MF DB esp w/ Leaf 80mp and Phase P65+!!! etc... as I have had a MF/DSLR.
I certainly would not attempt photo-journalism with my Cambo WRS. So my point is, you need to get the most appropiate system to work with your work flow.
Do have a look at Sinar arTec and actually play with it!
Good Luck