There is a firm in the US who sell a wide range of film holders for some Epson, Canon and other scanners. They are not cheap but what they offer may be of help.
The site is at
http://www.filmscanusa.net
I obtained from them a suitable 127 negative holder for my Epson V 500 scanner. As an example of what they can supply, here is their list for that particular model:
Epson Perfection Scanner models: v500, 4490, 4990, 3170, 3200, 3870, 4180, 4870
Available Film Sizes:
110 (16mm) Pocket Instamatic.
126 full frame (Instamatic), (28x28mm square frame)
APS (24mm) (IX240) (Kodak Advantix)
MINOX (9.4mm) (Sub-Mini)
16mm Movie / Microfilm
17.5mm Hit ( Mini )
8mm Movie
35mm Standard (Full Frame)
35mm Half Frame
35mm Xpan (two frame panoramic)
35mm Widlux (three frame panoramic)
35mm Lomography (capture sprocket holes)
127 (45-46mm)
120 (60mm)
70mm
Kodak Disc (15 frame round disc negative)
Custom Size (email if size you need is not on list)