As a 7D owner who has attempted landscape work I wouldn't really recommend it but for the sports aspect I can't really fault the 7D - apart from the low-light performance which is famously poor - my landscape work is usually ND filter, long exposure work so I'm never shooting higher than ISO100 anyway
but for regular landscape stuff I wouldn't want to use my 7D unless I had excellent weather.
the 5DII is far superior when it comes to low-light work since it's full-frame sensor isn't totally crammed with MP likes the crop sensor of the 7D. It's has been a long time favourite with landscape photographers - sure the 5DIII is out now but the average joe can't dig out that amount of cash.
I've seen a fair amount of excellent sports/wildlife work coming from 5DII shooters so the camera isn't exactly bad when it comes to shooting birds in flight or sports even if it's frame rate is lower and the AF system isn't all that great.
Buying a 5DII used is a great option, I bought my 7D used at around £800 ($1,200) for the body and I couldn't be happier - I'm currently looking to get a used 5DII this year as the used price will be dropping gradually.
Personally, if it were me buying and I didn't already have a 7D right now, I would go for the 5DII