I think the PalmOne and ThinkOutside keyboards are identical in size and shape. I have the ThinkOutside keyboard that works with my 4705, thats the good news, now for the bad news. They are correct when they say the 4705 will not fit. I purchased my keyboard for my PalmOne T3 so it didn't hurt much to try and mod it to fit my 4705. Here are some pics to show what I mean.
This is the part you have to cut out to make room for the extra length of the 4705.
As you can see the T3 fits, but with no room for any extra.
The 4705 needs just a little more length so I removed the section that you see in the photos.
It does not hurt anything except it does leave the end of the keyboard exposed. That is not a problem for me as it is in the case for travel.
Just be carefull to remove the section.
I would not do this to a new keyboard but it saved me some bucks and I had this one already.
Hope this helps.