Best way to handle the selection of multiple taxonomy terms

Hi there

I am working on a site that has about 1000 terms in one vocabulary. Eg:
Abrasives
Abseiling
Accommodation - Agents
Accommodation - B&B's
Accommodation - Backpackers
Accommodation - Bush Camps
Accommodation - Caravan Parks
Accommodation - Chalets
Accommodation - Cottages
Accommodation - Country Clubs
Accommodation - Country Hotels

What is the best way to allow multiple selects? I was thinking of using Taxonomy Super Select with check boxes and then editing the terms so that they had parents eg:

Accommodation
-- Agents
-- B&B's
-- Backpackers

Super Select then groups them according to parent in a collapsed fieldset. However even with the groups the list is going to be too long. I was also thinking of maybe having a two boxes the one of the left lists all the terms, the one on the right lists all the selected terms and then have buttons to add, remove terms. Does a module like this exist?

Any other ideas?

Thanks

James