Thanks for giving me a base to work off of! I created a lemon-rhubard custard cake the other day that was delicious. Added a bit of rhubard syrup and sugar soaked rhubarb chunks. The cook time was a little off for me. My cakes took a good 50-60 minutes. I used large and small ramekins. I also found that these cakes are still a little runny at the bottom when hot, but if you cool them in the fridge for a few hours you can turn them over onto a plate and they keep their form, like flan. Makes for a nice presentation.
Going to put up a modified recipe for the lemon-rhubarb cakes in the next few days on my blog. http://www.thegrumpygourmand.com ;)