I've been told that if you want a flatbed scanner that can do slides and film, you should go for an Epson V850 pro... problem is that this WILL upset the bank manager. The market for flatbeds with that option isn't there anymore, so you will not find many options available unfortunately. I have a flatbed for photos and documents and a separate Plustek 8300i scanner for my slide and film scans. You could have a look around for second hand Epson scanners of course.
Edit: Epson has a V600 model as well, which is significantly cheaper. You would have to compare the specs to find out where the differences are though. I think the V850 has a dedicated lens for film scanning, the V600 may use the same sensor for documents and film, but that's guesswork from me.