We have one of those tunnel tents, longlegted. But it's a Sunncamp Vario 9, so like those but with pods on either side as well. We can have it with 2 bedrooms or with the pods with 4 bedrooms. And yes, sites do take them, although we generally check the size of pitches before we go to make sure.
Vario 9.
We love it. It's the business. There are 4 of us, so we have a bedroom for dh and I, dsd and dd share (or dd in with us), the 3rd bedroom has all our clothes etc in and then the 4th one is used as a drying room for wetsuits and towels.
There's tons of room inside the main section. We had 13 lifeguards in ours last summer - and I cooked and served chilli for them all. We have a table, cooker on a stand, fridge, gas barbie and a toy box, plus a table for us to sit at!!
And yes, we have a trailer to put it all in. We keep everything stored in there, so when we want to go camping it's a case of hook up and go and we have everything we need. And because we have more room to take things I took our sunloungers this year and they were fab (and much fought over as we only had 2!).
We bought a 3 way camping fridge last year, so it runs on gas but also off the mains (not sure what the 3rd way is though ). It was our first year with hook up, which previously I thought was for wimps , but for a fortnight's holiday it was a godsend. No running up to the shop to change ice blocks over. Lovely chilled wine all the time!!