The Plustek OpticFilm 7200 & 7200i, 7300 & 7500i, 7400 & 7600i, and latest generation: 8100 & 8200i series are for 35 mm scanning, that's correct.
Plustek also do offer the OpticFilm 120 that can do 6x9 cm.
Pacific Image Electronics / Braun Phototechnik / Reflecta also have a medium format film scanner offering: PrimeFilm/FS 120 / MF 5000.
And there is the Epson Perfection V700, V750, now: V800, V850 range of scanners that allow for even greater formats.
While these can achieve the effective resolution as high as dedicated film scanner, the dynamic range is better and their versatility is greater.
All are good offerings, although can't be compared with medium format scanners that were around ten years ago:
The "modern" counterparts don't have qualities such as adjustable focus, multi-coated /-tempered lenses for best sharpness of both, infrared and RGB light (so that you can have best defects correction).
(You can focus with an Epson Expression 12000 XL (A3 scanner) or Microtek ArtixScan F2 (A4), but here where are talking typical flatbed scanning resolution results - which partly renders the option for focussing meaningless - and no longer having and IR lamp for auto-correcting dust and scratches from color film.)
But remember:
Quality is always also about the images you feed to a scanner and about what you actually need for your output purposes.
Knowing have you've got and what you finally need to achieve is more important than setting all parameters to max. 