The Speedgrader guide How do I use SpeedGrader? has said, "....xls/.xlsx files are currently in Crocodoc beta testing" for 'awhile' now. I have not heard or seen an update. This format is used a lot in our Econ and Accounting disciplines, among others, heavily and i would love to provide them an update on Crocodoc supporting this.
Thanks in advance for any info you can provide!