Where to buy small flat rotary encoders like those in mice?

I'm working on a wrist wearable, and I would like it to have a scroll wheel similar to the one on the Sansa e200 mp3 player:

https://www.google.com/search?q=sansa+e200&client=firefox-b-ab&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiXq5y0rtrXAhXnxFQKHSa5ARwQ_AUICygC&biw=1916&bih=971

I think I can use a rotary encoder like those you would find in a mouse. This is very close to what I'm looking for:

https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20171125103339&SearchText=mouse+rotary+encoder

However, those all appear to be the same. I'm going to be mounting it on a PCB and it would be nice to choose the best one from a few different options.

Most of the encoders I've found have long metal shafts. Is it generally possible to remove those and replace them with something flat?

You could try Mouser, Digi-Key, Allied, Jameco.

No shaft: https://www.digikey.com/products/en/sensors-transducers/encoders/507?k=rotary+encoder&k=&pkeyword=rotary+encoder&pv1989=0&pv545=170&FV=ffe001fb&mnonly=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25 And some of these have a pretty short shaft https://www.digikey.com/products/en/sensors-transducers/encoders/507?k=rotary+encoder&k=&pkeyword=rotary+encoder&pv1989=0&pv545=145&FV=ffe001fb&mnonly=0&ColumnSort=0&page=1&stock=1&quantity=0&ptm=0&fid=0&pageSize=25