Thanks for all of your help @macuser_22!
I ended up getting the return printable and e-fileable once I removed a TXF import with ~3000 transactions and entered a summary for the 1099-B instead. Based on what I've read, TurboTax Desktop shouldn't have problems handling that many transactions, but it appears that at least in my case that wasn't completely true (though it worked for my Federal and VA returns).
Glad to finally be able to finish my return for this year and I appreciate all your help troubleshooting.
