First, bravo and thanks!
Writing in contxt of use with Host 1.0 ... can we go with icons custom sized? 64x64 is fine for 99.99 of scrolling around - it's just that his tiles are 90 by 92.
It's not a "must", I can try to give the option of more sizes, but it's kind of tricky.
Windows Mobile doesn't have any API to convert to ICON, so I had to manually write the icon data (header, mask, data bits, etc), I originally did it with a 32x32 (see the Link2CPL tool) but found the icons where too small for my HD2. I switched to 64x64 (adjusting the header and data bits) so they look better with more detail.
One tricky part was the icon, the other was to "embedded" into the exe, again there is no functionality on .NET or Windows API to create resources inside a library. so the way I did it was to create a unmanaged exe with a 64x64 icon, and then replace the icon data inside.
I can try having different exes (let's say, one for 32, 64, 90, etc) and give that option, that should work, just need to redo the header and embedding code.
Does Host 1.0 resize the icons?, most apps do when they find a different size icon.