With a VPN connection with Cisco VPN Client and split tunneling enabled, does my outbound connection from the network I am VPNed into show my IP address as the source? I believe it does, but not sure.
Split tunneling refers to the idea that some packets will get encrypted and others will not.
Neither has to do with address translation.
So either path your packets take, the source IP will still be the same unless there is some other device/property to change that!
Now, depending on what KIND of VPN it is (client vs. tunneled network) that may change... If you get an IP assigned to you by the VPN, any packet going over the VPN would show as THAT source IP address, whereas anything NOT going to the VPN (split tunnel/local) would show your original IP as the source.