I am not sure to fully understand that hybrid EVF/OVF viewfinder (*) thing for the upcoming Fujifilm X100, but I am starting to think it could be a real meaningful innovation for future camera design.
And one of the very question could be: will this technology could ultimately kill the (D)SLR concept ?
Actually the very advantage of SLR / retractable mirror cameras is the “through-the-lens” (TTL) viewing (which is necessary for proxy/macro shots), metering (for natural light as well as for flash) and DOF preview. But this is at the expense of an additional and bulky mechanical device, as well as it requires bigger lenses (because the rear lens has to be more distant from the film/sensor), involves additional response lag (mirror flip) and a resulting darker and narrower viewfinder (only high end SLR have clear and 100% viewfinder).
With this new hybrid viewfinder technology – and assuming that further refinements will bring the EVF at the level of an optical SLR mirror system if it is not already the case with the X100 – you have basically all the pros of (D)SLR without the mirror and its cons. At least I can imagine that consumer and semi-pro DSLRs (that have a not-so-good viewfinder, frankly) will be quickly surpassed by this new technology, which I assume is even less costly to implement.
(*) by the way I am not sure about the – only -90% coverage of the X100 OVF that I mentioned in a previous post, though it was stated somewhere in the Fuji marketing documentation.