I just recently had the same issue but wanted something that could be used mainly with charcoal/briquettes to get the flavour back into the BBQ that you don't get from gas cooking. When I was a kid everyone did wood barbies and they tasted so much better. I think we have sacrificed flavour for convenience by going to gas and I really wanted to use briquettes to get the favour going.
Anyway I found these
www.echurrascobbq.com.au/ and have bought one. The eChurrasco by Everdure.
They use gas and can be used as a gas BBQ for the convenience factor if you want but mainly the gas is just to get the coals going so you can cook over them and get the flavour. You put the coals in and burn for 8 minutes with gas and then turn it off. Wait another 8 minutes and you're ready to go. Normally cooking with coals takes ages to get them ready but this speeds it all up. I've also bought the roasting hood so I can use it as a Weber kettle setup as well.
The cooking area is a bit smaller than normal BBQ's these days but given I mainly only cook for the family it wont be a problem.
I have discussed with the missus what we would do with a big event and given the coals are hot once they're going for a few hours and you don't have to worry about saving gas or putting it out you could extend the cooking period over a bit of time. Eg do some satay sticks to start, then the sausages for the kids and then the chops. A sort of degustation BBQ.
Here's some photos.
Pork Ribs
A butterfly'd chicken...
Lamb and spuds of course
My paella dish fits perfectly. Paella should traditionally be done over a real fire according to my Spanish friend Antonio.
The coals after just 15 minutes ready to cook with. I spread them out a little to give better coverage.