I hear you, and I had the same problem. Due to the dimensions of a full size iPad, any bag that will fit it tends to be of the sort that will carry more than just a camera and a couple of lenses, it's more like 3-4 lenses + a body. I ended up getting an insert for a regular women's leather purse that works well for me.
That said, here are some I've found and considered:
Billingham Hadley small - wonderful but expensive (will probably ask for this eventually as a birthday or holiday gift some year)
F-Stop Millar Shibata - I do own this one - got it in a recent 50% off sale, quite a steal, it's lighter weight than my purse+insert option
Tenba DNA series - not sure if the 8 will fit a full sized iPad, otherwise the 11
Timbuk2 Snoop Camera Messenger Bag 2014 version - looks like the small version will fit an iPad, but the XS version won't
Tamrac Zuma 3 - seems a little too tall to me
Tamrac Rally 5
There is another bag that was reviewed here recently that also will work, but the name escapes me. It comes only in brown, I think. Perhaps someone will remember the name.