Oh well, it wasn't such a vital issue for me as I've just ordered myself a Tranzport, which should arrive tomorrow.
A micro-receiver, along the lines used in Logitech's recent mouse/keyboard products, would have been more convenient for my situation, but I accept that's not necessarily the case for all users, whose needs may be different.
I already use an AlphaTrack with Ableton Live 8 on my main desktop computer and will be using the Tranzport with my laptop.
I won't need to use it at great distances from the laptop, let alone inside recording booths and suchlike, but the flexibility offered by wireless connectivity will be very convenient when I'm chilling out on the sofa with my DAW set-up on a little laptop table.
I have one of those Korg nanoKONTROLs at the moment but, despite the attractiveness of its layout, it has turned out to be quite a disappointment in practice. It's been very fiddly to set up with Live - no templates built in, unfortunately - whereas I know from my experience with the AlphaTrack that Frontier Design controllers are extremely easy to set up with Live.
I'll use it alongside a nanoKEY and nanoPAD, though, as they're pretty good products.