Can any of us think of a loli that doesn't appear to be underage? From Kiddy Grade, Lumiere is hundreds of years old, but she is most certainly a loli. Personally, I feel there is something about her that makes me think isn't isn't a proper loli though. Oh, never mind, its just her standard outfit. I absolutely can't stand it. When she wears other clothes She definitely is a loli. The point is that age isn't what matters, but they do have to look a certain age.
While I can't think of any right now, A character who was "born" a certain age physically is not a loli just because she is 1 month old. If that person looks 20, then she is no loli.
On a side note, I never considered Lina to be a proper loli. She is an ass kicking tsundere sorceress, but there is only a hit of loli. I feel she looks too old, mostly in the face. This is also, in real life, how you can tell small women apart from children. My brother for instance would probably be in jail if his girlfriend's face wasn't that of an adult. With her small child like body and squeaky voice (for those who thought the "cutesy female anime voice" wasn't physically possible, rest assured that it is) her face is that of someone in her 20s. Lina sufferers from the same problem.
[edit] Also, I wouldn't be so certain about the "innocent" part. Daiakuji, Inma Seiden, Love Doll, and Temptation for instance have characters who physicaly meet the requirements of loli, but there are girls who very much lack innocence. I can't remember all their names (the only noneinnocent-seeming lolis I can think of at all Rachel from Love Doll and Hitomi from inma Seiden) but all four have perverted little girls in them. There are plenty of examples, but typically in the other examples you can blame it on some form of brain washing.
Another questionable loli is Momiji from Momiji. Under certain circumstances her breast will enlarge leaving the realm of loli-ness. Also there is a little girl (who probably is suppose to be in collage

) with huge tits in Chains of Lust. The rest of her body is child sized, but her chest. Are these loli's as well.
[edit2] some non-hentai examples of loli without innocence would be PuniPuni Poemi's Punie, and Burn Up (I think X) Maya. Neither cases involve proper loli. Maya looks to be at a borderline age, and Punie doesn't sound like a little girl. Furthermore, both can be said to have some degree of innocents. The four H anime mentioned earlier have girls who most certainly are not innocent. Hitomi asides, they are sluts in small bodies. In fact I can't think of any decent examples (Inma aside) whom can't be described in that manner.