Not something I recall coming up.
Just been away camping for 5 days. On the 2nd day the temperatures really dropped (nothing dramatic, just past -0C) and I felt it in my feet. I had taken a 3/4 length ccf pad to suppliment my UQ but I couldn't get it sitting right between the hammock's layers and my lower legs were still cold.
Out of fustration I lopped the edges off with my camp knife to fit the tapered shape of my bag and popped it in - oh my it works well! Couldn't believe I hadn't done it before. Toasty all night. Infact my lower body was so toasty I could feel the transition in temperatures to my UQ across my bum.
I figure it's gonna work a lot better in a single layer hammock, too. Every time I've tried to sleep on a pad directly in a hammock it ends up sliding about and crunching up on the sides. This way it was still in good position by morning.
Anyone else do this?