The 5740 is anything BUT portable.

The HP 450wbt IS portable however: http://reviews.cnet.com/HP_Deskjet_4...tml?tag=series

Just how portable do you need? There is "portable" which requires it's own laptop bag, and then there is PORTABLE which can just fit in the laptop bag, these printers are usually tiny, like this tiny Pentax model:

http://www.adorama.com/IPXP200P.html