iLap user review.
Justin Blanton shares his opinion of the iLap.
Personally, I have a specialised laptop trolley … no laptop at the moment, but I have the trolley for it, ready and waiting (along with the wireless card and access point and the desire to work somewhere other than my home office).
If you use your laptop a lot in the same location, this could be good option, but I don't imagine it's something you want to be carrying with you everywhere.