This is probably going to be of no use to you, but hey, I'm bored
I spent ages looking for a reasonably priced-desk (I could afford) that would look ok in my bedroom and that was wide enough to fit my large multi-monitor setup. Out of sheer desperation - for some reason desks over 1.8m wide are just unheard of in about 99% of places - I ended up going for one of the modular Ikea offerings.
It isn't made out good quality materials, it was hideously difficult to fit in the car and it doesn't have two tiers. It required me to spend an hour fighting my way through Ikea like a sheep to get it... and once again when I missed out a leg the first time... and then more time to put it together, however now that is all in the past I've found I actually quite like it.
As for what it is... well, it is 2.2m wide and about 1m deep, surprisingly sturdy the size and structure / support, feels good quality once its set up, and most of all it was cheap! Can't remember exactly how much it cost, but I think it wasn't somewhere far either side of £200.
I also noted at the time that its part of one of their popular ranges which they are more than likely going to continue producing for at least the next few years, so if the surface were to ever wear out (the laminate can go horrible after a while) or I managed to break it in any way, I could buy a new surface for something like £40 and fit it in about 10 minutes.
So yea, I'd recommend you have a look at some of the 'cheap-and-cheeful' solutions. I think you're going to be paying more than £600 to get something off-the-shelf that meets your specifications, or as you said be be looking to have one custom made.
