The Stowaway Bluetooth Wireless Keyboard is an expensive but nice upgrade to your wearable office.
Pentax makes high-quality (but very expensive) portable printers.
Learn how to build your own low-cost battery chargers for Pocket PCs from EarthVillage's Pocket PC Battery Extender Guide.
Andy's Wearable Computer Resource is a great resource for details on building miniature, wearable computers.
SCOTTeVEST makes one-of-a-kind "personal area network" jackets and vests for concealing your wearable office in style.