I had a pennine trailer tent a long while ago. Easy to put up single handed and when you added the awning it was vast. I believe Pennine were bought out by Conway (or the other way round) but you can still get Pennine brand trailers.
They are fairly sophisticated now with 'fridge, cooker etc. built in. If I was in the market for one I would check out Pennine and Conway campers and then look for second -hand.