On checking the Carphone Warehouse Coming Soon section tonight I came across the Sony Ericsson X10 Mini Pro listed on there for launch sometime this July.
There is no information on possible pricing or networks but they at least have a coming soon date to get people excited. They also have the X10 Mini listed for a June release.
Both X10 Mini and X10 Mini Pro were announced back in February and are part of the new exciting lineup from Sony Ericsson this year
Link: X10 Mini Pro