Is it possible for IPCONFIG on Vista to display the status of one adapter only?

It's not as short as ipconfig, but you can use netsh to do this:

> netsh interface ip show addresses "Local Area Connection"

Configuration for interface "Local Area Connection"
    DHCP enabled:                         Yes
    IP Address:                           10.34.46.91
    Subnet Prefix:                        10.34.46.0/24 (mask 255.255.255.0)
    Default Gateway:                      10.34.46.254
    Gateway Metric:                       0
    Default Gateway:                      10.10.124.14
    Gateway Metric:                       0
    Default Gateway:                      139.30.107.176
    Gateway Metric:                       0
    InterfaceMetric:                      4245

Replace "ip" in the command by "ipv6" to get IPv6 information.

Put it into a batch for less typing :-)

netsh interface ip show addresses "Local Area Connection"

just a sidenote: This doesn't reflect the current state.

When I tried this solution to check the dhcp address, it wouldn't update the status until ipconfig was issued.