Have you looked at Duokan? Its Chinese but you can get rid of the Chinese books it comes with and you dont have to access the chinese bookstore. Transferring epubs is by itunes add/dragdrop, open in if you d/l from online, or transfer via browser to its buildin ftp server. Theres not much configgability in terms of colour but the four themes are quite presentable. You do get a dictionary define popup, but you get several options when you highlight a word (Copy, Digest - dunno what that is yet, Note, Define, Share or Search). You can add your own fonts via wifi, too which is a bit nice.
https://itunes.apple.com/au/app/duok...517850153?mt=8
All that said.. Marvin is on the brink of being released for iphone as part of Marvin 2.0 and you will likely find that fills all your needs and then some. I've pretty much given up on Shubook now.