Lexar ships first 128GB SDXC card

There's definitely s future for 128Gb cards.

I fully agree. The next Pentax (K-3?) whenever it may come will probably come with a Full Frame Sensor and more then 20MP.
Canon already is rumoured to bring out a new 5D MKIII or 6D with a Full Frame Sensor and 24MP. Nikon has a new camera in the mill as well that will replace the D3X. Both are supposed to be officially introduced this summer.
I spoken to a Pentax Rep in Germany on a long weekend away not so long ago (bumped in to him in 'Photo Dose' in Bremen) and according to him Pentax is looking to come back in to the market with cameras that at the higher end are targeted at the Semi-Professional Photographer.
So, by having a faster card with higher capacity makes complete sense and to standardise cards and speed is long overdue.
Technology gets better and failure of cards will come down all the time, even at the lower end. Just look at RAM as this has already shown the direction Solid State Memory could take.