As such, there is no limit for the number of VTP domains supported on CW2000(LMS). But the number of devices managed by it really does matter.There are 2 types of deployment :
Single server and Multiserver. Single Server can support upto 2000 devices and i am not very sure of Multiserver. More info on this is available at:
http://www.cisco.com/warp/customer/cc/pd/wr2k/prodlit/ckspp_wp.htm