You are right about the command
show ip bgp vpnv4 ip-prefix
For more information on how the Routes are distinguished and the use of BGP extended communities (route targets)
Check the below URL (scroll down to the image 7-4 VPN-IP Address Format for a graphic explanation)
http://www.cisco.com/en/US/products/sw/ps2346/ps99/products_configuration_guide_chapter09186a00800ee111.html
an example
Router# show ip bgp vpnv4 all 10.22.22.0
BGP routing table entry for 10:1:22.22.22.0/24, version 19
Paths:(5 available, best #5)
Multipath:eiBGP
Advertised to non peer-group peers:
10.0.0.2 10.0.0.3 10.0.0.4 10.0.0.5
22
10.0.0.2 (metric 20) from 10.0.0.4 (10.0.0.4)
Origin IGP, metric 0, localpref 100, valid, internal, multipath
Extended Community:0x0:0:0 RT:100:1 0x0:0:0
Originator:10.0.0.2, Cluster list:10.0.0.4