I've definitely got the bug - have just finished my second pair of trousers, this time for my eldest (5 and a half).
The actual trousers were just as easy to make as the previous pair (the gingham cotton was actually easier to work with), however I did run into problems with the patch and back-pocket.
I wanted to add something (mainly to stop them looking like a pair of pyjama bottoms) and had some brown corduroy scraps from a ruined pair of the boys trousers hanging around. It was an experiment really and I made quite a few mistakes - the main one being not realising that I should have attached the patch before I had sewn up the trousers. I also managed to stitch the front part of oneleg to the back part of the leg (twice!), had to unpick stitches several times and had to dismantle my sewing machine three times due to stuck thread (I think this might have been because of the bulkiness of the corduroy). The zigzag stitches on the patch and pocket are far from perfect but I like the way they look - and they suit my boy down to the ground.
I have to apologise for the grubby grey socks - this boy does not like to have bare feet for some reason.