I can't help you with a specific pattern for that but here's a more general tip. When you're playing any song don't worry about trying to sound exactly like the original. Sing the words (at least to yourself in your head) and then find a strumming pattern that seems to fit the mood of the song. Don't worry about making either the vocals or the uke sound like Rod Stewart - make it your song. If you just try to imitate the original, most people will compare you to the original and we always tend to come up short in those comparisons. Make the song yours and people are a little more inclined to enjoy the performance on its own merits rather than "scoring it" against the original.
Just my $0.02.
EDIT: Holy carp! I just saw a youtube video of Rod singing Maggie Mae on a 2009 Letterman appearance. I've never been a big fan but, dude, his vocals have really gone. Never thought I'd say that Rod's vocals could get worse... LOL
John
