Everything will get rooted, eventually, regardless of the state of bootloader. If you are REALLY curious about what a community can do with a locked bootloader, check out the xperia x10 forum here on xda. Sony stopped development for this phone shortly after they released 2.1, yet there are several extremely stable 2.2 Roms floating around, and a few 2.3.2 in development, thanks to the devs and a supportive community. A locked bootloader really doesn't concern me much, that's why we have xda, as long as the community is behind the devs, pretty much anything is possible.
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