best banana muffins ever

So last night I had 4 very ripe bananas that I didn't want to toss. I tweeted: "I have 4 overripe bananas I need to use ASAP. Suggestions?" Lots of tweeters came to my rescue, but these are what I opted to make - Banana Crumb Muffins. They are the best banana muffins I have ever tasted. I tweaked it a little to use what I had on hand (4 bananas instead of 3, whole wheat flour instead of all-purpose) and it was seriously amazing. The recipe says it makes 10. I got 14 out of my batch and only used about half of the topping. Warning - at the estimated 263 calories per muffin on the recipe site it's not a low-cal treat. But my mind is already turning and I have several substitutes I think I could make without sacrificing flavor. Next time I make these (and there will be a next time or my husband and kids will beat me) I may try those out. If it's a hit with the substitutes I'll share my version.