Miles & More (Lufthansa, Austrian, Swiss, and other partners) - Online Booking site for ex Germany flights

I want to book a MUC-LHR-YUL-YYZ---etc-SFO-LHR-MUC trip for my sister in business class prefarbly on Air Canada/British Airways. Does anyone know of a good website for online bookings similar to travelocity or expedia (and in english preferably)? Also does anyone know any good consolidators based in Germany or elsewhere who woul have good deals on Business Class/First Class fares oroginating in Munich?

Thanks in advance.

Greetings!
The UK is stuffed with consolidators whereas in Germany, the situation is a bit more dreary.
Most web engines I used in the UK such as

http://www.ebookers.co.uk/
http://www.trailfinders.com/index.htm (that one is said to be consolidtator for UA and I liked their service)

do occasionally find good D class fares but they are awfull for assembling anything that is not a straight return flight.

Originating from Germany, the most pleasant engine is www.travelclub.de.
If you hop straight into their expert mode (no doubt you are one), you can
toggel the language to English:
http://www.travelclub.de/de/index.html
It then displays something that is half German, half English but should be deciphrable to you.

It finds one way flight outbound from Europe as well and properly reads Amadeus (Lufthansa's forsaken reservation system) rules. But also here, I made mainly unpleasant experiences with cricle trips or open jaws.
The good thing about this site is that you can hold your reservations.

Sites that specifically offer consolidator fares, I know only in German language:
http://www.opodo.de
http://www.stockebrandt.de/body_reisen.html
praises itself for being a BA consolidator and stocks D fares. They are hard to deal with in German, it might be a true challenge to try Englisg for a change.

There is also a mediocre Orbiz clone which polls the quotes from different consolidators and should display them to you. It is incapable of showing you rules (ok that one is copied correctly from Orbiz) and gives zero information about routing and stopovers.
http://www.touristikboerse.de/

Personally, I find that the web's travel engines are getting worse and offer less good insight into assembling fares (expedia and itn are no exception).
Generally, I find you plan quite wise: BA offers excellent fares ex Germany (especially in D). So the setup would be to buy a return flight ex Germany via the UK (well that happens naturally with BA) which woud come close to your itinerary.

You did mention expedia, they of course do exist in Germany:
http://www.expedia.de
Unfortunately in German but equally stubborn as its bigger brother.

You might give it a try and pester BA Germany themselves. They gladly give you adivse which travel agent to use for a fare type ... probably because it saves them from doing work for you...
http://www.britishairways.com/travel/home/public/en_de
This site is available in English btw.

Good luck!

www.vornesitzen.de are also good and offers F & C fares ex-germany. Contact details under Info-> Kontakte