is it semantic/acceptable to put paging (NEXT/LAST, etc) links in a <tfoot> of a statistical table element?

I would say yes, that would be acceptable.

Traditionally, the <tfoot> is usually used to duplicate header information when a table must be broken across boundaries (think printed pages and things of that nature). It also can be used as a static footer when the <tbody> elements are rendered in a scrolling panel. I believe that is close enough to what you're trying to do.

As a side note, I'm glad to see you've placed the <tfoot> before the <tbody>. I can't begin to count how many times I see people put it at the bottom.