Group tour/trek in yunnan

Actually, it's pretty easy to travel on your own in Yunnan and meet up with other travellers who're doing the same.
One outstanding hike would be the Tiger Leaping Gorge one. If you're adventurous, you could also add on the part for Walnut Grove -- Haba.
Cheers!

I am with ellyse. Many foreign backpackers travel in Yunnan on their own, and it's easy to find follow trekkers on the way. Both Tiger Leaping Gorge and Meili Snow Mt./ Yubeng are great places to trek. Now is the right season for Tiger Leaping Gorge. Meili Snow Mt. range is for autumn. 2 Useful links for you:
Tiger Leaping Gorge
Meili Snow Mt.

you can find an agency easily but i don't think they will send an english guide especially for you.

Just finished doing two Chinese language tours out of Chengdu - mixed feelings about them. Saved a bundle of money (shocking statement isn't it - I spoke to 2 travellers who paid 1500Y each just for the flights into Jiazhaigou, and I paid just under 1800, which included airfare, two nights in 3+ star hotels, transfers to the sites of interest, breakfasts and 3 meals, single supplement.) In exchange, I had to endure several shopping stops and non-stop "entertainment??" by the guides in fluent chinese on the buses. Other than terrible breakfasts, the other meals were quite good, especially on the Jiazhaigou trip. I did begin to get irritated by being told to hurry, and then having to wait for some others!

I really enjoyed the interchanges with the chinese travellers (I speak English only), who were, without exception, friendly and seemed to really enjoy that a foreigner was travelling with them. I had a similar experience with a day trip out of Liajiang last year to Tiger Leaping Gorge.