As
pied piper said above, British Telecom guys do indeed use a ruggedised laptop, e.g. the BT chap who fitted my ADSL connection earlier today had one.
Specifically it was a
Panasonic CF27 'Toughbook'. <- Click the link, for more info on that range of laptops (Nb. it would appear that the model he had has since been superseded)
Now, on close inspection, it was built to almost field-of-combat levels of ruggedness which accordingly (obviously) made it a tadge heavy - in spite of being housed inside a Titanium case - but it hosted all the usual ports and connectors.
What was especially neat though was the built-in integrated wireless GSM communications capability - I even saw him use it to remotely (re)configure our phone line.
That said, you could probably do much the same with a dedicated (e.g. on airport) wireless LAN (indeed I've actually done this recently at our airport home base - we've got rid of a 64kb leased line, and replaced it with a 10Mb WLAN - spanning a distance of approx 1.5 miles, with ease ! )
In any event the BT engineer was quite happy his laptops performance, indeed nearly as much as I am with my new ADSL connection !