Trailer Questions

[electricsheep]

I am thinking about getting a trailer. I would prefer a 2 bike trailer that can be converted to occasional single bike use.
The main brands that I have found are

Brenderup
Lider
Trelgo
Erde

Are there any others that I should be looking at ?
Any thoughts on these brands/trailers ?
Any good places to look for used tralers ?
Is there anything that I should lookout for when buying

Thanks
Rob

[webbyc]

There's a site on the web, not sure of the address, but its name is the Trailer Warehouse, worth looking at.