A small update.
I couldn't find a set of standard Predator Sponsons plus weapons within my budget of $10. But I was able to score a pair of Baal Predator Sponsons.
The Blood Angel marking were scraped off with a hubby knife. I also drilled out the barrel. For now Deathbot will have to settle for Heavy Bolters, but I will magnetize the assembly so that Lascannons can be added at a later time.
Here is the tank assembled and waiting for primer.