I'll vote for the Clavinova - they have a really nice feel. the same range as an upright, and a fantastic sound. They also have a lot of the basic electronic functions like backing tracks. You can find one second hand on ebay for £200 if you're patient.
The other option is to have a look on your local freecycle/gumtree and see if anybody wants rid of an upright piano, but you can't practice those quietly and they take up more space.