im afraid cloth pullups that have enough absorbency for a big toddler wee in the night do get abit bulky like a nappy - usually they pullup though.
have a read through this forum...i found these similar past threads

hth's
http://www.nappycino.com.au/forum/no...-pull-ups.html
http://www.nappycino.com.au/forum/no...-trainers.html