Cargo/long bikes

The CTC Magazine (sent to CTC members) often has articles covering cargo bikes. Might be worth having a root around the CTC Forums at http://forum.ctc.org.uk/ to see if anyone there can advise.

I used to have a Kona Ute, used it for commuting and lugging stuff to my vegetable plot. It was great fun but the novelty wore off after about two years and I sold it on, mainly due to it taking up too much space at home - if I had the room I might have kept it as I do miss it sometimes when I have something to carry and don't want to drive. They are quite awkward to manhandle when not riding, especially when loaded, but ride quality was really good - I enjoyed riding it a lot. My early model Ute had some niggles like lack of rear mudguard and puny front forks but Kona resolved all my issues with the later models they produced. Worth bearing in mind if you get a 2nd hand one.

My main advice would be to check that the model you're looking at is compatible with what you want to do with it. By that I mean, for example, the Kona Ute will not easily take anything other than the bags that come with it. That means that almost the whole market of bike-specific luggage is closed to you. That got really annoying after a while, especially when I found most child seats wouldn't easily fit either. They will carry a significant amount more than a normal bike, something I only appreciate now I don't have one any more. I used to strap a big crate to the deck.

Other things to consider might be:
Kickstand - when fully loaded you need a stand so you can open gates, find your keys etc.
Puncture resistant tyres (I won't say puncture-proof), mine had Conti City Contact and they were good
Somewhere to keep it. Sounds obvious but they are a bit awkward to wheel around in tight spaces

I got my from Evans but this place is worth a look,they have lots of accessories and bikes:
http://www.practicalcycles.com/index.htm
There are also lots of cargo bike blogs if you have the time to search for them, I've not got any links handy, sorry.

One last thing - be prepared for people coming up to you and asking you "what's it for?" which you would think is a daft question but I got it all the time.