Without charting, you can't really confirm whether or not you have Oed. I totally hear ya on the co-sleeping and night nursing making accurate temping hard, though!
Anyway, to answer you question - yes. Some women never get a positive OPK but they do, in fact ovulate. Different OPKs have different levels of sensitivity. Also, you may have had a short surge before you started testing twice a day and missed it then... or it may be yet to come.
Ah... the mysteries of the BFing, no PPAF body...I have no idea what is going one with my body at the moment either.
I'd say just DTD whenever you have fertile CM (if possible). That way, if you do O, you'll likely time things right. (Doesn't meant you'll catch the egg, but at least you'll be in the running.)
Mama and co-parent to our beautiful DS (08/08) and our mighty strong DD (04/10) . Life is good.