there is a little workaround you can do with Photoshop, or even with the Gimp.
open your huge texture in photoshop and set the ruler's units in pixels (no inches or centimeters)
Set the grid size to 1024 px, or lower.
With the slice tool tesselate your image following the grid
Save it all for web as pure jpg (with no html code atached)
Photoshop will save automatically each tile with progressive number in a desired directory.
Open Sketchup and with the ruby "massmaterialimport.rb" (available at http://www.crai.archi.fr/RubyLibraryDepot/Ruby/RUBY_Library_Depot.htm) create a new material set.
Now subdivide the face you want to texturize, keeping the some proportions of the Photoshop grid and apply each texture to the corresponding subface. Scale it correctly and you will have a seamless match.
This is longer to explain than to do, once you have practiced a bit.
Here are a couple of images of a work in progress. The facades are texturized joining several tiles. When I exported it to indigo it worked flawless.
The cons are, of course, that your poly number will increase, and all the thing is a bit tricky. But it works.
/matteo
belasi-temp1.jpg
belasi-temp2.jpg