I did this last year using Wyeast 1007 German Ale. It worked out really well, and I'm planning to use it again this year. The major drawback is the beer won't clarify like a good oktoberfest should, but this yeast is a really nice alternative if you don't have lagering capabilities. It's a clean fermenting yeast that works really well for this style.
JRBrewer on Untappd
Planned - Belgian Dubbel
Fermenting - 7C's IPA, Cyser
Bottled - Oktoberfest Ale, Honey Saison, White IPA, Lincoln Park Spruce Ale, Cherry Cider, Belgian Strong Ale, Pumpkin Stout, Cream Ale, Wheat Graf