As far as unavailability goes, Haven and I are walking the West Highland Way from the 23rd of August to the 1st of September, so will be unavailable then.
I've been having a quick look online to see where there are any decent bodyboarding spots, and Machrihanish (a 4 hour drive from Glasgow) seems to be the best bet, with a lovely looking campsite (
http://www.campkintyre.com/), but there?s a lot of travelling involved to get there (I suspect probably too much). On the other coast there seems to be a few spots around St Abbs Head (about an hours drive from Edinburgh) that are recommended, and Haven and I know a few good places to stay in that area (it's a 30min drive from Barns Ness campsite which we have stayed at in the past (
http://www.scottishcampingguide.com/link.php?n=255&c=6)). There are also some cottages to rent in Coldingham (
http://www.eastlawcottages.com/, and
http://www.watchbadgers.co.uk/) which look nice, but are obviously more pricey than camping. Other than this there seems to be little in the way of good bodyboarding places (all those islands get in the way!), but there is some good white water rafting and loads of canoeing in the Trossachs that I?d love to try!
The other option accommodation wise to camping, is Youth Hostels, which would cost less than ?10 a night, or there are various places like the one ThatBird has posted up, and this one by Loch Tay (
http://www.assc.co.uk/defaultpage121c2.aspx?pageID=59&propertyid=57), and depending how many people were going they would probably be worth taking a look at.
These are just my first thoughts on this, and I guess that it would be best to get a good idea of the numbers of us going before deciding on the best type of place to stay!