Film holder question from a beginner

[Graeme Hamilton]

Hello LFPF, I have recently entered the world of large format photography with a rather mint Calumet CC-400. New to 4x5, and not looking to drop $700 on a fancy 4x5 epson flatbed just yet, I picked up a used Canon CanoScan 9950F flatbed scanner for not much. I think the scanner will serve my needs (at least to start), but the problem is it didn't come with any film frames (yes the specs say it is transparency capable and it initially came with a 4x5 frame). Unfortunately I have been unable to turn up any used 4x5 frames on the net. So there's the back ground, here's my question, Do any of you have any experience in making film holders from scratch? Does anyone have a photo of a stock one or measurements I could use to duplicate?
I've been lurking here for a few weeks, and know the community here is so helpful and patient with us noobs. Thanks in advance for any advice.