[Butch Cassidy Slept Here]

First, I would NOT look upon Sun Country Air as a viable alternative to Delta/Northwest. I only mentioned Sun Country because they seem to have non-stop (seasonal) service MSP - TPA.

The other options, like Delta/Northwest, involve a change of planes. However...

MIDWEST AIRLINES offers its change of planes in an airport less congested than Detroit---Milwaukee.

CONTINENTAL AIRLINES offers a change of planes in Houston. While Houston is probably comparable to Detroit in terms of congestion it is less prone to snow/ice than is the case with Detroit. However the potential for Continental to try to re-route you through Newark, NJ remains.