Yep. I like the idea. I've been looking at a cheap, tiny little laptop that I'm planning to get soon. I'm still debating whether or not to install Linux on the thing (I know folks, I know, not this thread though, please?)

I just see two little problems.

First is that I'll either need to have a cellular modem for the thing, or make sure I have wifi access when sending (not a guarantee in my area.) Fortunately, my smartphone can take care of this, but now should I want to spend bitcoins someplace, I'll be juggling the laptop AND the smartphone.

Second, is that now I'm carrying a laptop around with me. The one I'm looking at is small, but it's not pocket-sized. Encryption and backups let me keep my bitcoins secure if anything happens to the laptop, but still, the laptop itself is a bit of a concern: it costs more than I'd ever keep online.

Obviously, neither of these two issues is insurmountable. In fact, I'll probably go ahead and experiment with this. But for now my only real answer to having portable bitcoins is to use an online wallet, keep the amount stored in there VERY low (ideally only shove coins in just before heading out the door, and transfer them back as soon as I get home), and to NOT trust the site, instead behaving as if they will eventually disappear.