Most Bluetooth-enabled smartphones allows you to connect a bluetooth keyboard and mouse. Stowaway Bluetooth Keyboard is a brand that specifically designed for phones and PDAs.
However there is no external display connectivity on any BlackBerry devices. If connecting to a external monitor is essential for you, some Windows Mobile phones and the iPhone are able to do so with the correct adapter. I am not sure about Symbian, nor the Palm Pre (not yet released here in the UK).
I'm looking for a smart phone that can be hooked to a portable display and have a monitor out display, do blackberry have these two options?