>How do you get the cellular mod for a pro-26?  I thought it couldn't be
>done.

1) Modify the unit so it receives the Cell "images" in the UHF part of 
   the spectrum. There were/are a couple of web sites but one is/was
   http://www.n-link.com/~friendly/pro26cell.html
   
2) If you want to actually restore the frequencies "Blcoked" on a US
   model so you can actually "key them in" then your only option is to 
   replace the main IC with the one used on the PRO-26 in Europe. 

Hope that helps.