If it is really difficult to resize C: and your concern is the space taken up by files in sdmcache (software dist downloads etc.) then you can relocate that.
This is from a 9.5SP2 client. You will need to restart after this, but providing you don't have any nasty permissions set it can be relocated to a different drive.
Not too bad if you just have a few exceptional systems and should cause too many headaches with support. Just be careful if you ever redeploy the agents.
Mark McGinn
MarXtar Ltd/MarXtar Corporation
http://landeskone.marxtar.co.uk
LANDESK One Development Partner
The One-Stop Shop for LANDESK Enhancements