Yes, the 903 is pretty heavy. I haven't heard of a stand specifically for it, but not everything needs a
specialized product.
As for reading PDFs, this doesn't tell us much. I have PDFs of comics, technical books and reports, multipage datasheets and even (somewhere) books preformatted for some ereader. The contents matter far more for your needs than the format.
The forums likely depend on how you want to load them. In my limited experience, accessing web forums directly from the 903 is clumsy.. and it would be much harder on anything less. One weakness is the browser doesn't rotate easily.