Dual battery-powered wireless receiver?
 

So I'm going on a trip to the UK and I want to record some video with my 7D of two people with audio. I want both to have lav mics. However I'd like to avoid too many of those darn receiver boxes. Is there a system out there that has two receivers built into one box?

Audio Technica 1821 receiver and 1801 transmitters. I've been using it since almost the day it came out and as long as you don't use the supplied mics it is absolutely an awesome unit. YOu can run to seperate channels or mix the 2 receiver sides to 1 channel, you have a certain amount of record level control on the receiver, clear scan, nice range of freqs to choose from, the transmitters have the ability to go from -6db to +12db.
Get something like Countryman EMW B3 or B6, Sanken COS11, Tram50 or AT 899s and you're good to go.
To me the only drawback is the cables. The input to the receiver is TA3F (mini XLR) and the cables are only 18 inches long so it can be somewhat limiting. You can however get long cables made up (or do it yourself).
In short, the best 2 channel unit made-of course the only others I known of is Azden and I know a few people that use the Azden duals and honestly I wouldn't. Audio is too important to me.

Lectrosonics SR... if you have the budget!

It's no good bringing any radio equipment from the USA - it is likely to be illegal in the UK and you may get it confiscated if you are unlucky.

Licence-free you can use 863-865 MHz in the UK.

With a shared (mobile) licence you can use UK channel 69 - 854-862 MHz.

All the above are Sennheiser evolution version "E" (USA uses versions A, B and G)

None of these are usable in the USA.

It's best to hire radio kit in the UK - Richmond Film Services is the best place to start.

Jeff, I never knew Lectro had one. Sweet unit. Thanks for the info.

John, Good point. Missed the part about the OP using the gear in the UK. Gotta wear my glasses when I read posts.

I'd endorse everything John said - we always rented in wireless equipment when we worked overseas - not only because of the legality point which John mentioned quite correctly but also because you can't be sure that the frequencies of your gear aren't used for some other purpose in the country where you'll be working. Thus your equipment could not only be illegal (which is bad enough) but useless too.

There are times when cabled gear has an edge; maybe this is one?