Many thanks for these links and pointers - but I may not have framed the question properly.
The residents are all residents of a particular sim - one of the original Nova Albion regions - and some of us rent or own land here with venues. What we'd like to do is to use our lands to have a party in celebration of what a great sim we live/work in, to attract residents from further afield and show off the community feel here. So renting some other region sorts of misses the point (my fault for not being specific enough).
What we would particularly need is the ability to stream music onto the street - I'm sure that is possible, if rarely allowed - for one day only, and some other input from SL management to assist us in our quest to focus on the region. In return we'll provide free entertainment to visitors, stalls, space for build and newbie workshops.
Think of it as a festival-meets-carnival-meets street party. I'll check out the links you sent me, but I'm also interested in contacting an SL manager because we feel that encouraging higher footfall in a region, making it an occasion, building community are all things that help the Second Life project as a whole
Best
Ian