I want to create a chart/spreadsheet with multiple rows and multiple columns and then insert links to other DT documents in the cells. Is this possible now (or in the future? 
)
I don’t know about the future.
The “sheet” document type (Data > New > Sheet) is essentially a plain-text CSV document displayed in row/column format. It does not support links of any sort.
Documents such as RTF, Formatted Note, Markdown, and HTML do support links. Tables can be made in most of them – most easily in RTF and Formatted Note. Several of the built-in templates contain examples of tables that include DEVONthink links.
If you do a ‘Copy Item Link’ on a document in DTPO, paste that into a cell in a sheet document, you can then select that cell and do an Open URL. That will open the linked document in a new window. It isn’t much, but it works.
I finally figured out how to do what I needed to do by rereading your post Korm. I’m posting this (spelling this out) for any other people who know as little as I do about different programs, because it is a very helpful tool.
I made a table in a Word document and saved it as a rich text document (rtf); then dragged the .rtf into a DT database. now I’m able to copy many different page links from w/in DT and paste them into a cell in the table. Better yet, I can add a number of links into one cell. they all open perfectly. I can’t figure out how to additional additional rows to the new table, yet, but I can just make a different formatted table in word and do the same thing again - it’s simple enough. 
In RTFs, tables can be created, and columns or rows added or deleted, using the panel that opens when one choose Format > Table … in the DEVONthink menu. (The same action applies to OS X’s TextEdit and a number of other RTF editors.) To use the Table tool, place the cursor inside the table.
Though it’s simple to use Word (or Pages) to make tables, the Table tool can achieve the same in an RTF created in DEVONthink.
If you want to regularly make documents that have tables, you could create one (or import one) that you want to make into a template. Use File > Export > As Template … and save it to ~/Application Support/DEVONthink Pro 2/Templates.noindex. Then, when you want a new document based on the template, use Data > New from Template …
Thanks Korm - much easier - especially because I can then go in and add additional rows and columns. This will be very helpful.