But... you still CAN buy the book.... The majority of books from Kobo are available in both formats.
After buying it, head to
http://www.kobobooks.com/library/reading.html which is Kobo's I'M READING list.
Next to the book should be an icon "ADOBE DRM EPUB". Clicking that will download an ACSM file which, when you open it will invoke Adobe Digital Edition to download the DRM infected DRM file.
Now, back on the web site, select the book and then the DELETE button. This ONLY removes the book from your reading list, and ensures that if you DO launch the Kobo Desktop, that it will not download the kobo format, and also, if you use WiFi on the Touch that it will not download the Kobo format either.
You can still see all books you have purchased on the website by going to the PURCHASED tab
http://www.kobobooks.com/library/purchased.html If you select a book here and the BOOKMARK button it will be re-added to the I'M READING tab.