Depends on your definition of scanner.
I run an Icom R2500 comms receiver with a P25 board fitted and it has by far the best P25 audio out of any of my radios and scanners. AOR also make a P25 board for some of their high end receivers. Both the Icom and AOR scan but don't 'trunk track' unfortunately.
Of course, another option is the USB TV dongle SDR/DSD route, although it is early days for these systems, they will get more polished as time goes by and more developers get on board the SDR bandwagon. This may be the biggest threat to the Uniden and GRE scanners of the world..
Why buy a $500 digital scanner, when you can plug a $100 funcube dongle receiver into your little 7" notebook and start receiving DC to >1Ghz in all conceivable analogue and digital modes?
Interesting times, to be sure..
What can go wrong, will go wrong!
FuncubeDongle Pro+ - PSR600 - PSR500 - BCD996XT - BCD396XT - TM9155 - IC-208H, amongst others :-)