7+ Players in Carcassonne - Problematic?
You might want to consider getting another expansion or two -- with the base set plus Inns &amp; Cathedrals, you'll have 90 tiles (72 core + 18 expansion) to play with.  Assuming seven players, you'll have 12-13 tiles per person to play with.  

Traders &amp; Builders will give you an extra 24 tiles to play with, including some really funky shapes for finishing those hard-to-finish cities.

If you want to keep the game shorter, you can just use the two sets listed.