Hello Jay,
I've been considering dipping my toe into the water as well, but I'm put off by the long contracts as you mentioned. However, some of the PAYG mobile contracts that are cropping up look like they might be worth a punt.
You'll have to pay for the modem, but generally they are less than £50 so not a huge outlay. 2 deals that look useful are 1 from T-mobile, which is a flat fee of £2 a day, but only on the days when you use it - this might work if you are only travelling one/two days a week, for example? Or the other one I've seen is from Vodafone, quite expensive at £15 for 1GB, but this stays usable for 365 days, unlike most of the others which expire after 30 days.
Although it's undoubtedly going to be a more expensive way of surfing on PAYG, it might be worth it to try coverage etc. as you're travelling. If you're happy with a given service, you could then plump for a fixed term contract to bring the costs down.
That's the way I'm looking at it at the moment, anyway.. HTH.
Cheers,
Gaz