Laptop shot craps, no access to my Sonar discs. Will I have to buy it all over again? I see DL links for some of my purchases on my account page, but not for Sonar or Dim Pro. 

SONAR 8.5 is no longer available from Cakewalk. It may be in a bargain bin in a store... somewhere. I don't think it was ever downloadable.
Upgrade to the latest program, X3. As a registered user, you'll get a discount and it's downloadable.

The full version of 8.5 was only available as a set of DVDs. SONAR 8.5 was the first version available as a download. To reduce the size of the download version it was only sold as an upgrade and required SONAR 8 be installed. SONAR 8 only shipped as DVDs. Since then all downloads are full versions just like the DVDs.

Short answer is no, there is no way to obtain 8.5 from Cakewalk. You'll have to dig up those disks, borrow a set from someone or upgrade to the current version. I suppose you could try pleading your case to Cakewalk Support, but that's not likely to get you anywhere. They won't even talk to you about 8.5 issues.

At some point you would need to upgrade anyways so might as well do it now. 
Go for X3 Studio and you'll have all the same stuff as 8.5 plus a lot more. I think only True Pianos is missing from studio. The upgrade from 8.5 is on sale right now for $99 for you. That's a bargain for what you'll get. 
 
http://www.store.cakewalk.com/b2cus/ProductInfo.aspx?productid=10-CXSS3.00-30E