Ok Hadd here's a couple of suggestions.
The space for the Ribs is turning out to be an issue, Glenuig Inn have 10 private moorings at £10 a night, they also have a smart bunkhouse or en suite rooms, unfortunately the owner is a bit of a "merchant banker" so I wouldn't recommend eating there, check out Trip Advisor! Us locals aren't welcome and food and drink is pricey.....but he has moorings!
Sunnyside Croft has one Lodge and one static, prices are £420 & £380 respectively, unfortunately the campsites around here are just that.... Campsites, they don't really do statics
If Glenuig doesn't suit then there is the new secure pontoon at Mallaig, I was hoping the harbour master would phone me back this evening but he didn't.
The area around Mallaig/Arisaig is known as The Road To The Isles, it has its own website
I am situated about half an hour from Mallaig and we have 4 properties we rent out. Woodlands Cottage has a double and twin, Fassfern Cottage also has a double and twin and Fassfern house sleeps 10. Although its not in Arisaig we are just down the road and I could give safe storage for 6 or 7 Ribs. links below.
Fassfern House.... http://www.cottages-and-castles.co.u...ernhouse*n406/
Fassfern Cottage..... http://www.cottages-and-castles.co.u...ncottage*N407/
Woodlands Cottage...... http://www.cottages-and-castles.co.u...-Cottage*N408/
Hope this is of some help.