There are several previous threads on this subject if you haven't already searched them. You didn't say how many frames or what quality you are trying to achieve which might dictate one solution over another.
In my film days there were slide duplicators that copied 35mm slides to slide or negatives. Some used a macro lens, others included a lens. You can still find them on Amazon and elsewhere. B&H has one - http://www.bhphotovideo.com/c/search?ipp=100&atclk=Accessory+Type_Slide+Duplicating+Accessories&ci=713&N=4037060703+4291393134+4247364404
Don't know of anything that will handle larger negatives with this approach other than a copystand with a light table. If you have a lot of images, the best bet is a flatbed scanner IMO.
You need to look at your whole workflow including software that can handle negatives. I scan mine to achieve at least HD (1920x1080) resolution - 1600ppi for 35mm film. This is good enough for most uses. I keep both a jpg (2-3Mb) and dng (19Mb) for each image. I can always rescan individual frames later at a higher resolution if needed.
I visited my local photo lab the other day and found they used a flatbed scanner similar to mine for odd sizes. I have a Epson V750 Pro which has done a nice job on everything I handed it: 110, APS, 135, 127, 126, 120, 4"x5", and even some Minox 8x11mm. Some formats required adapters that fit the frames provided with the scanner. A benefit of the flatbed is scanning multiple frames at a time, from 2 4"x5" to 12 35mm slides or 16 35mm negatives. Much less setup time on your part when you can batch scan. Scanners with DigitalICE or similar can perform an additional infrared pass to idenitfy dust and scratches depending on the software you use.
I used VueScan to scan several thousand images so far. It has profiles for many different types of film to do the color conversion for me and does the infrared pass that eliminates most touch up I would have to do otherwise.
