This is how mine turned out:
30 lemons (~5kg, whole)
4kg brown sugar
500ml honey
1 cinnamon stick
yeast nutrient
ale yeast
champagne yeast
Boiled the flesh of the lemons in about 20 litres of water for 45 minutes. Brown sugar added once boiling. Yeast nutrient added at 20 minutes (remaining). Cinnamon added at 10 minutes. Zest of 20 lemons added at 5-10mins. Honey added at 5 minutes.
Made up to 28L of 1.070 with preboiled water. I'd have gone thinner, but I was running out of space in the fermenter.
Originally was going to use wyeast 1007 (german ale) for the bulk of fermentation, but had trouble getting it started so added a generic ale sachet, which worked very slowly. Champagne yeast added after 5 days. Both were started in a light (1.030) dextrose/lemonade/wort starter.
I have also prepared a vodka extraction of the zest of 10 lemons, which will be strained and added to the brew before bottling.
Taste so far is promising, though the brown sugar has added a heap of colour, so it will definately be an odd looking lemonade. It should finish up pretty dry, so I plan to drink it sweetened over ice in when the weather warms up.