I have completed several cleanses and have experienced cramps in my calves. Unlike you though, I do wake up occassionally in the night with this pain (and have since I was about 18 I think) and tend to ache quite badly after exercise here too. I think its from wearing high heels and not getting enough salt! I have also experienced back pain during cleanses, but not otherwise. I wouldn't worry as it seems that aches and pains are part of the cleansing process and they should subside afterwards.
I have completed a couple of 7 day cleanses as well as 10, 14 and 17 day cleanses. I would say that I only truly started to feel a real difference after 14 days (although like most people I felt back to normal after 4 or 5 days). So to me, there isn't much difference between doing 7 or 10 days!
Good luck and I hope the cramps go, I know how painful they are! Claire