I used to work at Roehampton University
http://www.roehampton.ac.uk/ as part of ICT team
The university leases all of it hardware - computer et al - but not there servers
With the hardware we could upgraded and change computers totally or put our own DVD RW/RAM or anything else we needed etc in them as long with brought them from the leasing company (the price was not too much more then buying for the high street+admin fee)- if anything went bag big time we could change/have a new computer delivered the next day at no cost - but look at the small print - some times this is not covered at all or there is a limit of X number of times they replace a computer them after that you pay big time
We could change and do what we want with the software
like all contract and leasing you need a VAT number if based in the UK to do this
for this experience this work well with the university - we where using IBM kit made in China and the university had between 700-1000 PC on two campuses
Mark